RU175578U1 - PIEZO ELECTRIC FILTER - Google Patents

Abstract

The utility model relates to electronics. The device comprises a mold base, a lid forming a detachable connection with a base, six terminals on each long side of which are opposite each other, two of which are located diagonally relative to each other and passing through through holes filled with dielectric material, two other extreme pins located diagonally relative to each other are made of two parts, the first of which is located in the upper part of the base, and the second from the opposite side Considerations under the first portion and the remaining terminals are located in the upper part of the base in blind holes filled with a dielectric material. In the middle part of the base, on its long sides opposite each other, two metal plates are installed, each of which is made with a curved edge located closer to the edge of the base. Plates made stepwise and shelves of steps located on the findings. Six capacitors located three on each long side of the base between the terminals located in the blind holes and connected to the racks of step-like plates. In this case, the middle capacitors are additionally connected to metal plates with curved edges, five sequentially placed piezoelectric quartz rectangular plates, the longitudinal axis of symmetry of each of which is located along the crystallographic axis Z ’. On each surface of the plate there is an electrode having one contact pad in the corner part of the surface, while the electrode on one of the plate surfaces is additionally equipped with a contact pad located diagonally relative to the other contact pad of the electrode, and contact pads are additionally located in the remaining corner parts of both surfaces . Each contact pad located in each corner part of one surface is electrically connected to the contact pad located below it on the opposite surface. The technical result consists in the ability to select the upper or lower sideband of the spectrum of the modulated signal. 3 ill.

Description

The utility model relates to radio electronics, in particular, to piezoelectric technology, and can be used in frequency selection devices on one side band with a nominal frequency of 5 MHz. More specifically, a utility model relates to a piezoelectric filter structure for mounting in openings of a printed circuit board.

Piezoelectric filters are a resonant acoustic system using the principle of energy capture and are designed to distinguish a certain frequency band from the general spectrum. Filters contain at least one rectangular piezoelectric plate with one or more pairs of exciting electrodes placed on its working surfaces (faces) with electrical leads forming resonators, while the number of resonators determines the so-called filter order.

A known piezoelectric filter comprising a piezoelectric element located in a ceramic-metal casing having a common electrode on one of the plate surfaces and two or more input / output electrodes on another surface paired with a common electrode and two or more intermediate electrodes between the input and output electrodes, and a plurality of adjusting electrodes contacts connected to the front intermediate electrode, and a plurality of adjustment contacts are electrically connected to the input / output contact and the ground contact, and the wash electrode is electrically connected to the ground terminal (JP application 2000138561 (A), published May 16, 2000).

A disadvantage of the known piezoelectric filter is the use of a single piezoelectric element, which does not allow you to select the upper or lower side band of the spectrum of the modulated signal.

A known piezoelectric filter containing two piezoelectric plates placed in a ceramic-metal casing, each of which contains two separated electrodes formed on one of the surfaces, and one common electrode formed on the other surface. Each of the piezoelectric plates has discharge electrodes formed in three of the four corner parts of the plates, while the electrodes of one of the plates are offset by the relative electrodes of the other plate (patent JP 5949445 (B2), filing date October 26, 2012, published July 6, 2016).

The disadvantages of the known filter include low resistance to mechanical factors associated with the fastening of piezoelectric plates at three adhesive points.

As the closest analogue, a piezoelectric filter is selected, which contains a ceramic-metal casing for surface mounting, which has a detachable connection with a cover, as well as at least two external contact pads made on its base and at least one pair of piezoelectric placed in the casing plates with two pairs of exciting electrodes each and at least one matching capacitor, in addition, the housing has two systems of internal contact pads, one of which is designed for like a high-frequency electrical signal, and the other is intended for grounding, these two systems of internal contact pads are placed in the same plane in two mutually parallel rows so that in each row the internal contact pads of one system alternate with the internal contact pads of the other system, and each internal contact pad one row is opposite the inner contact pad of another system from another row, with each piezoelectric plate and each matching condensation the torus is electrically connected to the inner contact pad of both systems, in addition, the housing has a metallization layer both on its outer surface and on the inner surface, with the exception of the areas occupied by the external contact pads and matching capacitors, while the metallization layer forms a closed circuit, electrically connected with a system of grounded internal contact pads (patent RU 2373636 C1, filing date 02.10.2008, published 20.11.2009).

The disadvantage of the closest analogue can be attributed to the fact that it is not possible to single out the upper or lower sideband of the spectrum of the modulated signal in it.

A common disadvantage of the known piezoelectric filters made in metal-ceramic cases is the complication of the installation of piezoelectric elements in them, which, in turn, leads to the need for special equipment. In addition, the cermet housing does not provide for the use of additional matching elements, which will not allow to provide the necessary amplitude-frequency characteristic of the filter.

A technical problem, the solution of which is provided by the claimed utility model, is the creation of a piezoelectric filter design intended for installation in the holes of a printed circuit board having a tenth order.

The technical result obtained by using the claimed utility model is the ability to highlight the upper or lower sideband of the spectrum of the modulated signal.

The technical result is achieved in that in a piezoelectric filter containing a rectangular base, a cover forming a detachable connection with the base, sequentially piezoelectric quartz rectangular plates with electrodes with contact pads located on their surfaces, and capacitors, according to the utility model for each long side of the base opposite each other, six conclusions are established, the two extreme of which are located diagonally relative to each other, performing They pass through the through holes filled with dielectric material, the other two extreme leads, located diagonally relative to each other, are made of two parts, the first of which is located in the upper part of the base, and the second on the opposite side of the base under the first part, and the remaining conclusions located in the upper part of the base in blind holes filled with dielectric material, in the middle part of the base along its long sides opposite to each other are two metal plates, each of which is made with a curved edge located closer to the edge of the base, metal plates made of step-like and step shelves are located at the terminals of at least six capacitors located three on each long side of the base between the terminals located in the blind holes and connected to racks of step-like plates, while the middle capacitors are additionally connected to metal plates with curved edges, while the filter contains at least five piezoelectric plates, the longitudinal axis of symmetry of each of which is located along the crystallographic axis Z ', while on each surface of the plate there is at least one electrode having one contact pad in the corner of the surface, while the electrode on one of the plate surfaces is additionally equipped with a contact pad located diagonally relative to the other contact pad of the electrode, and in the remaining corner parts of both surfaces are additional contact pads, while Dye pad located in each corner portion of one surface electrically connected to the contact pad situated beneath it on the opposite surface.

This internal structure of a piezoelectric filter made using a metal-glass housing designed for installation in the holes of a printed circuit board is characterized by a multi-level arrangement of the main components of the device in the housing and, subject to the required relative positioning of the piezoelectric plates, capacitors and step-shaped metal plates inside the housing, filter nodes, which at the same time provides both an increase in guarantees relative relative attenuation, and increasing the order of the filter.

The present utility model is illustrated by the drawings shown in FIG. 1-3, an example of the implementation of a piezoelectric filter on which, however, is not the only possible, but clearly demonstrate the possibility of achieving the claimed technical result. At the same time, the given example of the implementation of the piezoelectric filter does not limit the possibilities of implementing the utility model that do not go beyond the scope of the utility model formula and is not exhaustive.

In FIG. 1 shows the structure of a tenth order piezoelectric filter. In FIG. 2 is a cross-sectional view of this filter. In FIG. Figure 3 shows the construction of a piezoelectric element in the form of a second-order unit for a piezoelectric filter of one side band.

With reference to FIG. 1-3 are indicated:

1 - base;

2 - cover;

3 - piezoelectric quartz plates;

4, 5 - signal electrodes of the plate 3;

6 - contact area of the electrode 4;

7 - contact pad electrode 5;

8, 9 - contact pads;

10, 11 - contact pads of the electrode 12;

12 - grounding electrode plate 3;

13, 14 - contact pads;

15 - through conclusions of the base 1;

17 - composite findings of the base 1;

20 - deaf conclusions of the base 1;

16, 21 - dielectric material;

18 - the first part of conclusions 17;

19 - the second part of conclusions 17;

22 - metal plates with curved edges;

23 - stepwise metal plates;

24 - capacitors.

According to a utility model, the piezoelectric filter contains a rectangular base 1, a cover 2, which forms a detachable connection with the base 1, at least five consecutive piezoelectric quartz rectangular plates 3 with electrodes (Fig. 1). The longitudinal axis of symmetry of each plate 3 is located along the crystallographic axis Z ’. At least one electrode is located on each surface of the plate. On one of the surfaces of the plate 3 there are an electrode 4 and an electrode 5, which can be designed to excite a signal (signal electrodes). The electrode 4 is the input, the electrode 5 is the output. The signal electrodes 4 and 5 are made with contact pads located in the corresponding angular parts of the surface of the plate 3, the signal electrode 4 has a contact pad (terminal) 6, and the signal electrode 5 has a contact pad 7. On the same surface of the plate 3 in the remaining (free , unoccupied, empty) corner parts are additionally located contact pads 8 and 9, which are electrically connected (for example, by metallization at the end of the plate) with contact pads 10 and 11 on the opposite surface of the plate 3 (f ig. 3). The contact pads 10 and 11 are part of the electrode 12 located on the opposite surface of the plate 3 and are located diagonally relative to each other.

The electrode 12 can be designed for grounding (grounding, low potential electrode). In this case, the grounding electrode 12 may contain two peripheral parts a and b and one middle part c located between the peripheral parts a and b (Fig. 3). In the free angular parts of this surface of the plate 3 are additional contact pads 13 and 14 (Fig. 3), electrically connected to the corresponding contact pads 6 and 7 of the opposite surface of the plate 3.

On each long side of the filter base 1, six leads are installed opposite each other, two extreme of which 15 and located diagonally relative to each other, made through through holes (through leads 15) filled with dielectric material 16. Two other extreme leads 17, located diagonally relative to each other, made of two parts 18 and 19 (composite leads or ground leads 17). Part 18 is located in the upper part of the base 1, and part 19 is on the opposite side of the base 1 under part 18. The remaining leads 20 are located in the upper part of the base in blind holes filled with dielectric material 21 (blind terminals 20). In the middle part of the base 1 along its long sides opposite each other, two metal plates 22 are installed, each of which is made with a curved edge located closer to the edge of the base 1 (Fig. 1). The filter also contains metal plates 23, made stepwise and shelves of steps located on the findings 15, 17 and 20 (Fig. 1, 2). The filter also contains six capacitors 24 located three on each long side of the base 1 between the terminals 20 located in the blind holes and connected to the racks of the step-like plates 23. The middle capacitors are additionally connected to the metal plates 22 with curved edges.

The piezoelectric filter operates as follows.

The piezoelectric filter system includes a series of individual strip-type piezoelectric plates 3 made of quartz. Each plate from the series of piezoelectric plates 3 is connected by electrically conductive fastening elements (glue) to step-like plates 23, which in turn are soldered to the through leads 15, to the ground leads 17 and to the insulated blind leads 20. When applied to the electrodes 4 and the peripheral part b the electrode 12 of the piezoelectric plate 3 from the through terminal 15 of the high-frequency modulated signal with a frequency corresponding to the main oscillation of the shift in thickness, a shear is set in the sub-electrode region standing wave. Due to the acoustic coupling between the frequency resonators formed by the pair of input electrodes 4 and 5 located on the working surfaces of the piezoelectric plate 3, the shear vibrations of the input resonator are transmitted to the sub-electrode region of the output resonator formed by the pair of output electrodes 5 and the peripheral part a of the electrode 12. The output high-frequency modulated the signal from the first plate from the series of piezoelectric plates 3 is fed to the input resonator of the second plate from the series of piezoelectric plates 3. Then, similar transformations of the high-frequency modulated signal occur before the filter output (through output of output 15). Matching capacitors 24, necessary to obtain the desired amplitude-frequency characteristics of the filter, are placed on the racks of the step-like plates 23, as well as on the curved edges of the plates 22 under the piezoelectric plates 3 using a conductive fastening element. The piezoelectric filter is covered with a cover 2 and sealed by laser welding.

The utility model can be used in the manufacture of piezoelectric filters of one side band, which can be used as components of portable communication devices, in navigation systems, in communication and control equipment or in multi-cavity systems with other end uses.

Claims (1)

A piezoelectric filter containing a rectangular base, a lid forming a detachable connection with the base, sequential piezoelectric quartz rectangular plates with electrodes with contact pads located on their surfaces, and capacitors, characterized in that six are installed on each long side of the base opposite each other conclusions, the two extreme of which and located diagonally relative to each other are made passing through the through holes, fill dielectric material, the other two extreme leads located diagonally relative to each other are made of two parts, the first of which is located in the upper part of the base, and the second is on the opposite side of the base under the first part, and the remaining leads are located in the upper part of the base in blind holes filled with dielectric material, in the middle part of the base along its long sides opposite to each other are two metal plates, each of which is made with a curved edge, located closer to the edge of the base, metal plates made of step-like and step shelves are located at the terminals of at least six capacitors located three on each long side of the base between the terminals located in the blind holes and connected to the racks of the step-like plates, while the middle capacitors additionally connected to metal plates with curved edges, wherein the filter contains at least five piezoelectric plates, a longitudinal axis of symmetry of each and which is located along the crystallographic axis Z ', while on each surface of the plate there is at least one electrode having one contact pad in the corner of the surface, while the electrode on one of the surfaces of the plate is further provided with a contact pad located diagonally relative to another contact area of the electrode, and in the remaining angular parts of both surfaces additional contact areas are located, with each contact area located in each corner oic portion of one surface electrically connected to the contact pad situated beneath it on the opposite surface.

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