High-frequency piezoelectric element in the form of an inverse mesa structure

Abstract

This utility model relates to piezoelectronics and can be used to manufacture high-frequency resonators, generators, and monolithic filters. The technical result of the utility model is to increase the resistance of the piezoelectric element to external factors and improve the dynamic impedance of resonators. The high-frequency piezoelectric element is manufactured from a monocrystalline plate of arbitrary shape in the form of a thinned central part of arbitrary shape with a flange on both sides of the plate at the edges having breaks. Electrodes are located on both sides of the thinned portion of the plate. Contact pads are located on both sides of the plate edges. The breaks in the flange, located on opposite sides of the plate, do not intersect. The breaks in the flange contain contact pads connected to the electrode by current leads passing through the breaks in the flange. 2 fig.

Description

[0001] This utility model relates to piezoelectronics and can be used to manufacture high-frequency resonators, generators, and monolithic filters. The technical result consists of increasing the resistance of the piezoelectric element to external factors and improving the dynamic impedance of the resonators. The high-frequency piezoelectric element is manufactured from a monocrystalline plate of arbitrary shape in the form of a thinned central part of arbitrary shape with a flange on both sides of the plate with discontinuities at the edges. Electrodes are located on both sides of the thinned portion of the plate, and contact pads are located on both sides of the plate edges. The breaks in the flange, located on opposite sides of the plate, do not intersect. Contact pads are located in the breaks in the flange at the edges of the plate on both sides, connected to the electrode by current leads passing through the breaks in the flange.

[0002] A piezoelectric element is known, realized in the form of an inverse mesa structure on a round plate with cross-shaped electrode coatings applied to its surface (patent RU 2232461, published on 10.07.2004) [1]. The disadvantage of such a piezoelectric element is the absence of a break in the beads and, consequently, the location of a part of the current leads and contact pads on the thickened part of the plate with a transition through a vertical wall. It is known that high-frequency crystalline elements in the form of an inverse mesa structure are obtained by chemical or plasma-chemical etching and the transition between the thinned part of the plate and the bead has the form of a vertical wall, and in some cases is etched in the direction of the edge of the plate, which, when applying electrode coatings, can cause breaks in the area of ​​​​the current leads and contact pads and lead to deterioration in the dynamic resistance of the resonators.In addition, this type of plates and electrodes is intended for installation in housings for volumetric installation of the NS-45 type or similar, i.e., it limits the possibility of unification of housings.

[0003] A piezoelectric element in the form of an inverse mesa structure is also known, made from a single-crystal rectangular plate in the form of recesses made on both sides of the plate in the central part in the form of ovals with surrounding flanges, while excitation electrodes are applied to them on both sides of the plate, electrically connected to the corresponding contact pads on both sides of the plate (patent RU 196148 U1, published on 18.02.2020) [2]. A disadvantage of such a piezoelectric element is the lack of breaks in the flange for placing current leads and contact pads, which can lead to ruptures of the sprayed film coatings of the current leads on the vertical wall separating the thinned part and the flange, and deterioration of the dynamic resistance of the resonators. In addition, the fixed shape of the piezoelectric element (rectangle) and the thinned part (oval) is intended for use in surface-mount housings, but does not allow installation in bulk-mount housings, i.e.limits the possibility of unification of cases.

[0004] The closest technical solution to the claimed utility model is a high-frequency piezoelectric element in the form of an inverse mesa structure, made from a single-crystal plate in the form of a thinned central part with a thickened flange surrounding it, wherein the flange is provided with a gap, the width of which is 20-400 thicknesses of the thinned part of the piezoelectric element (patent RU 209985, published on 20.12.1997) [3]. The technical result of the solution is to improve the electrical characteristics of the piezoelectric element (monofrequency, dynamic resistance). At the same time, based on the figures provided, it can be concluded that the gaps in the flange are located opposite each other on opposite sides of the plate, which does not allow the current leads and contact pads to be located in these gaps, since this will lead to a short circuit of the electrodes during installation of the piezoelectric element.The current leads and contact pads are necessarily located on the thinned section and a thicker flange with a transition along the vertical wall, which can lead to poor electrical contact between the electrode and the contact pad and reduce the resonator's dynamic resistance. Furthermore, it should be noted that piezoelectric elements requiring the formation of an inverse mesa structure for strengthening typically have a frequency above 60-70 MHz, while the energy capture region that enables vibration excitation is approximately 0.3 mm. Therefore, the presence of a strengthening flange has virtually no effect on the piezoelectric element's frequency response. It should also be noted that discontinuities in the flange located opposite each other, i.e., the thinned section extending to the edge of the plate, reduce the plate's mechanical resistance to external factors.

[0005] The objective of the utility model is to increase the resistance of the piezoelectric element to external influencing factors and to improve the dynamic resistance of the piezoelectric element.

[0006] The proposed high-frequency piezoelectric element in the form of an inverse mesa structure is made from a single-crystal plate of arbitrary shape in the form of a thinned central part of arbitrary shape with a flange on both sides of the plate along the edges that have breaks, while the breaks on opposite sides of the plate do not intersect, on the thinned part of the plate on both sides there are electrodes, on the edges of the plate on both sides in the breaks of the flange there are contact pads connected to the electrode by current leads passing through the breaks in the flange.

[0007] The problem is solved by the fact that the thinned part of the piezoelectric element is completely surrounded by a flange, since opposite to the break in the flange on the opposite side of the plate, the flange does not break, which ensures the resistance of the piezoelectric element to mechanical impacts, at the same time, the electrodes, current leads and contact pads are located on the same level without crossing a vertical step, which ensures unbroken electrical contact between the electrode and the contact pad and, accordingly, improves the dynamic resistance of the piezoelectric element.

[0008] This utility model is illustrated by drawings (Fig. 1, 2).

[0009] The claimed utility model operates as follows:

[0010] When an alternating voltage is applied to the excitation electrodes 2 and 3 of the piezoelectric element, which are connected via current leads to contact pads 4 and 5 located in the gaps of recess 6 of the single-crystal plate 1, acoustic vibrations are generated. When the frequency of the exciting alternating voltage coincides with the natural frequency of the thickness-shear vibrations of the thinned section 6 of the plate 1, resonance occurs, and the conductivity of the device increases sharply.

[0011] Sources of information:

[0012] 1. Miniature high-frequency filter quartz resonator with improved monofrequency and small spread in dynamic parameters. Utility model patent RU 2232461 C2 IPC H03H9 / 13 (S.N. Kibirev, B.V. Sivkov, N.I. Alekseeva, E.A. Garmanov.

[0013] 2. High-frequency piezoelectric element in the form of an inverse mesa structure. Patent for utility model RU 196148 U1 IPC H03H9 / 02 (2006.01) N.N. Sigutin, M.S. Poyarkov.

[0014] 3. High-frequency piezoelectric element. Patent for utility model RU 2099858 C1 H03H9 / 02 (1997.12) O.E. Martynenko, S.I. Dzyba, D.I. Kolondadze.

Claims

A high-frequency piezoelectric element made from a monocrystalline plate of arbitrary shape in the form of a thinned central part of arbitrary shape with a flange on both sides of the plate along the edges having breaks, on the thinned part of the plate on both sides there are electrodes, on the edges of the plate on both sides there are contact pads, characterized in that the breaks in the flange, located on opposite sides of the plate, do not intersect, in the breaks in the flange there are contact pads connected to the electrode by current leads passing through the breaks in the flange.

Images