JPS6338578Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a piezoelectric vibrating component that is used by being incorporated into various electronic circuits.

<Prior art> Figure 1A shows a conventional piezoelectric vibrating component.
1 is a piezoelectric substrate polarized in the direction of the arrow,
Excitation electrodes 12 divided into two parts in the polarization direction are provided on one side of the substrate 1 to face each other, and each electrode 12 is provided with a lead-out conductive path 4 and a lead wire attachment electrode 5, respectively. Such a known piezoelectric vibrating component is oriented in the direction of vibration of the substrate 1 as shown in FIG.
A standing wave as shown in is considered, and odd-numbered harmonics of the fundamental vibration r ₁ appear.

<Problems to be solved by the invention> Conventional piezoelectric vibrating components such as those described above oscillate because the frequency response of the vibration is an odd harmonic of the fundamental wave _r1 of vibration, as shown in Figure 2. There were problems such as frequency jumps or picking up other signals.

<Means for solving the problem> This invention was made to solve the problems of conventional piezoelectric components as described above. In a piezoelectric vibrating component that produces a widthwise vibration mode by forming multiple excitation electrodes with gaps between them, the number of excitation electrodes is determined by the widthwise dimension of the substrate being W, and the odd harmonic order used being n. is n+1, the width dimension of the two outermost electrodes in the width direction of the substrate is substantially W/2n, and the width of the other electrodes is substantially W/n, and the odd harmonics to be used are The electrodes are connected to each other so that they are in phase with each other in the vibration standing wave, resulting in a two-terminal configuration.

<Example> FIG. 3A and FIG. 4A show the piezoelectric vibrating component of this invention.

In FIG. 3, a substrate 1 is made of piezoelectric ceramic polarized in the direction of the arrow, similar to the conventional example shown in FIG. A pair of inner excitation electrodes 3 facing each other are provided on each of the electrodes 2 and 3 to form a quarter electrode, and each electrode 2 and 3 is provided with a lead-out conductive path 4, and a lead provided in the width direction at the end of the substrate 1. The wire attachment electrodes 5, 5 are connected to lead-out conductive paths 4, 4 alternately provided in opposite directions from the opposing electrodes 2, 3.

When the width of this substrate 1 (length in the polarization direction) is W, the harmonic order of the fundamental wave is n, and the wavelength of the n-th harmonic is λn, the number of polarization divisions is n+1, and the width of the outer electrode 2 is 1/2nW. = 1/4λn If the width of the inner electrode 3 is 1/nW = 1/2λn, in the case of the embodiment shown in Fig. 3, the number of electrode divisions n+1 is 3+1=4 and the width 1/2nW of the outer electrode 2 is 1/2. ×3W=1/6W The width 1/nW of the inner electrode 3 becomes 1/3W, and the standing wave becomes as shown in Figure 3B, and the width W/6 of the outer electrode 2 _becomes 1/4λ. The width W/3 of the electrode 3 corresponds to 1/2λ ₃ . When this is excited with a fundamental wave, the charge distribution induced on the electrode surface is as shown in FIG. 5A, and when excited with a third harmonic, it is as shown in FIG. 5B. In the case of fundamental wave excitation, the electrode divided into four parts becomes the charge distribution shown in Figure 6A, and the positive and negative charges cancel each other out.
However, when exciting with the third harmonic, positive and negative charges are distributed alternately between the electrodes as shown in Figure B, so connect the in-phase electrodes in sequence as shown in Figure 7.
By essentially having a two-terminal configuration, only harmonics that are odd multiples of the third harmonic _r3 are produced as shown in FIG.

FIG. 4 shows an example of the electrode structure when using the fifth harmonic.

In this FIG. 4A, the substrate 1 is made of piezoelectric ceramic polarized in the direction of the arrow as in the conventional example shown in FIG. Each pair of inner excitation electrodes 3 facing the excitation electrode 2 is provided to form a six-divided electrode, and each electrode 2 and 3 is provided with a lead-out conductive path 4, which is provided at the end of the substrate 1 in the width direction. The lead wire attachment electrodes 5, 5 are connected to lead-out conductive paths 4, 4 provided alternately in opposite directions from the opposing electrodes 2, 3.

The standing wave in this case is as shown in Figure 4B, and the standing wave in this case is as shown in Figure 4B.The number of electrode divisions n+1 is 5+1=6.The width 1/2nW of the outer electrode 2 is 1. /2×5W=1/10W=1/4λ ₅ The width 1/nW of the inner electrode 3 becomes 1/5W=1/2λ ₅ , and only harmonics are odd multiples of the fifth harmonic frequency r ₅ .

In the above embodiment, the present invention was applied to a resonator, but it goes without saying that it can also be used for electrodes of oscillators, filters, trap elements, etc. that utilize piezoelectric vibration.

<Effect> The piezoelectric vibrating component of this invention has the above structure,
It has the effects listed below.

When the dimension in the width direction of the substrate is W, and the odd harmonic order used is n, the number of excitation electrodes is n+1, and the width dimension of the two electrodes located at the outermost side in the width direction of the substrate is substantially The width of the other electrodes is set to W/2n, and the width of the other electrodes is substantially W/n, and the electrodes are connected to each other so that they are in phase with each other in the odd harmonic vibration standing waves used, resulting in a two-terminal configuration. Therefore, a considerable number of the fundamental wave and odd-number harmonics that cause jumps in the oscillation frequency or pickup of other signals are suppressed.

Therefore, the drawbacks of the conventional piezoelectric vibrating component having a simple two-part electrode are reduced, and the reliability and stability of the vibration characteristics are significantly improved. In addition, the peak-to-valley ratio between the resonant frequency r and the anti-resonant frequency a increases,
Since the degree of mechanical coupling Qm increases, favorable results can also be obtained for resonators and the like.

[Brief explanation of the drawing]

FIG. 1A is a perspective view showing an example of a conventional piezoelectric vibrating component, FIG. 1B is an explanatory diagram of the standing wave of the same as above, FIG.
Fig. 4 shows each example of the piezoelectric vibrating component of this invention. In each figure, A is a front view, B is an explanatory diagram of each standing wave, and Figs. 5, 6, and 7 are 3 FIG. 3 is an explanatory diagram of electrodes of a piezoelectric vibrating component that utilizes third-order harmonics, and FIG. 8 shows a resonator frequency characteristic curve that utilizes third-order harmonics. 1...Piezoelectric substrate, 2...Outer electrode, 3...Inner electrode.

Claims (1)

[Claims for Utility Model Registration] A piezoelectric vibrating component that generates a widthwise vibration mode by forming a plurality of excitation electrodes with gaps in the widthwise direction of the piezoelectric substrate on one side of a piezoelectric substrate polarized in the widthwise direction, When the width direction dimension of the substrate is W, and the odd harmonic order used is n, the number of excitation electrodes is n+
1, the width dimensions of the two electrodes located at the outermost sides in the width direction of the substrate are substantially W/2n, and the widths of the other electrodes are substantially W/n, and the odd harmonic vibration to be used is A piezoelectric vibrating component whose electrodes are connected to each other so that they are in phase with each other in a standing wave, resulting in a two-terminal configuration.