CS210480B1 - Piezzoceramic rezonator of the by diameter vibrating longitudinal vibrations with suppressed parazite rezonances - Google Patents

Description

The present invention relates to a piezoceramic resonator oscillating in thickness-longitudinal oscillations with suppressed parasitic resonances.

The piezoceramic resonators used so far, oscillating in thickness and longitudinal oscillations, have, in contrast to resonators, crystal shapes of parallelepipedes or circular plates. With these resonators, only a wide spectrum of oscillations around a characteristic operating frequency can be achieved. Due to the different mass load in the oscillating resonators in a direction perpendicular to the thickness (especially the edges), there are formed more edible resonant oscillations, which generally have a different frequency from the characteristic resonator thickness oscillation, but with this characteristic oscillation. This results in a series of undesirable oscillations in the vicinity of this characteristic resonator oscillation, which is associated with a reduction in its quality factor and hence a reduction in the energy recovery efficiency for the characteristic oscillation of the resonators. and

The aforementioned drawbacks are suppressed by the invention, the essence of which is that its thickness profile is rounded or beveled on at least one side.

The advantages of the invention reside in the fact that by adjusting the profile of the thickness resonators, the oscillations generated in the less stressed parts of the resonators with the frequency of the characteristic resonator thickness oscillation are uniform. This results in a better resolution and a higher quality factor of this oscillation, and thus a higher energy efficiency in the operation of piezoceramic resonators.

The invention will be explained in more detail in seven figures, showing three possible embodiments of the invention, wherein FIG. 1 shows a side view of the tapered piezo-ceramic ring resonators described in Example 1, FIG. 2a showing the admittance oscillation spectra near the working thickness oscillations of this resonator 2b after the chamfer has been performed. Giant. Fig. 3 shows a side view of the rounded piezo-ceramic ring resonators described in Example 2; Fig. 4a shows the admittance spectra of oscillations near the working thickness oscillations of this resonator before rounding; and Fig. 4b after rounding. Giant. Fig. 5 is a front elevation and Fig. 6 is a side elevational view of the tapered piezoceramic rectangular resonators described in Example 3;

210488

Example 1

Circular resonator, shown in Figure 1, made of piezoceramic material zpolarizovaného based solid solution titanate-lead-lanthanum manganate (Pb _0, 93La _0j 04) + (Ti _{0 0} 9gMn 02) O3 MEI diameter r = 12.52 mm , a thickness of 1 mm and a bevel angle 2 of the upper surface 3 = 1.7 degrees and a bevel angle 2 'of the lower surface 3' was 1.7 degrees.

Figure 2a shows the oscillation admittance spectra in the vicinity of the piezoceramic resonator working thickness oscillation before the thickness profile 1 and in Fig. 2 'after the thickness profile 1 has been adjusted. These figures (2a, 2a') show the positive effect adjusting the resonator thickness profile (1).

Example 1 and d 2

Circular resonator, shown in Figure 3, made of zpolarizovaného piezoceramic material based solid solution zirconate titaničltanu lead strontium (Pb _{about 9} 2SR _O, O8) (ZrO ^ Thio-JCB has a diameter r = 38 mm and a thickness of 6 mm, and the radius curvature 4 Upper surfaces 3 r = 87 millimeters up to 3 mm from the edge and radius 4 'bottom surface 3' r = 409 mm up to 7 mm from the edge of the resonator Figure 4a shows the admittance spectra of the oscillations near the piezoceramic working thickness the resonator before and after the thickness profile 1 has been adjusted in Fig. 4b, and it is clear from these figures that the adjustment results in a positive result;

Example3.

Resonator rectangular shape as shown in FIGS. 5 and 6, made of zpolarizovaného piezo-ceramic material, a solid solution of lead zirconate titanate Pb (Zr ₀ 6oTio.4o) blended with 03 "2 mol% of MnO (MnOj having dimensions 7x4x1 mm. The chamfer 2 of the upper surface 3 was = 10.8 degrees to a distance of 2 mm from the edges of the sample.

Figure 7a shows the admittance spectra of oscillations near the working thickness oscillation of the piezoceramic resonator before the adjustment of the thickness profile 1 and Figure 7b after the adjustment of the thickness profile 1. From this figure it can be seen that the adjustment of the thickness profile 1 of this resonator .

Claims (5)

A piezo-ceramic resonator oscillating with thickness-longitudinal oscillations with suppressed parasitic resonances, characterized in that its thickness profile (1j) is rounded or tapered on at least one side. Piezoceramic resonator according to claim 1, characterized in that the chamfer (2) on one of the main surfaces (3 or 3'J perpendicular to the direction of the longitudinal longitudinal oscillations) is in the range of 0.01 to 45 ° to a distance in the range of 0.1 up to 50% of the maximum length of the resonator. Piezoceramic resonator according to claim 1, characterized in that the chamfer of the two main surfaces (3, 3 ') perpendicular to the direction of the longitudinal oscillations is in the range of 0.01 to 45 ° to the distance from the edge of the resonance of the primer in the range of 0.1 to 50. % of the diameter or width of the resonator. 4. Piezoceramic resonator according to claim 1, characterized in that the rounding (4) of one of the main surfaces (3 or 3 ') has a radius in the range of 0.1 to 20 times greater than the largest longitudinal dimension of the resonator and is spaced apart. 0.1 to 50% of the resonator diameter or width. 5. Piezoceramic resonator according to claim 1, characterized in that the curvature of the two main surfaces (3, 3 ') has a radius in the range of 0.1 to 20 times greater than the largest longitudinal dimension of the resonator and is made to a distance of 0.1 to 50. % of the diameter or width of the resonator.