JPH04192909A - Composite trap - Google Patents

Abstract

PURPOSE:To decrease cost and to reduce an area occupied by a base by fixing two trap elements on one base and constituting them as a single equipment by projecting three lead terminals from the base. CONSTITUTION:The end parts of three lead terminals 5-7 are connected and fixed to the terminal parts of pull-out electrodes 2-4 pulled out onto one side edge part of a base 1. First and second trap elements A and B are parallelly connected and fixed onto the base 1. A terminal electrode 13 for input of this element A, terminal electrode 17 for ground, terminal electrode 14 for output, terminal electrode 23 for input of the element B, terminal electrode 27 for ground and terminal electrode 24 for output are respectively connected to the pull-out electrodes 2-4 formed on the base 1 and simultaneously mechanically fixed. Afterwards, dip coating is executed around the base 1 by a rubbery elastic body 40 and further, dip coating is executed for the surroundings by armour resin 50.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a trap circuit for removing a specific frequency signal contained in a signal.

[Conventional technology]

In television receivers, reception interference may occur not only from the audio signal but also from other FM signals.

One of the countermeasures is to use SIF traps not only for single-frequency traps at 4.5 MHz, which correspond to audio signals, but also at 4.8 MHz, where the energy density of interference waves is high. , 5.05
A configuration consisting of a three-frequency trap with MHz added is currently effective.

To realize this three-frequency trap, conventionally, ceramic traps for three frequencies, that is, three ceramic traps, have been used. As a result, costs increase and
There was a problem in that a large board area was required to mount the three trap elements on the circuit board.

In order to solve these problems, the applicant has:
We proposed a trap circuit in which traps consisting of two dual-mode ceramic resonators with different frequencies are connected in parallel (
Jikganpei]-85945).

In this case, one trap has two pairs of vibrating electrodes with the same electrode area, and the other trap has two pairs of vibrating electrodes with different electrode areas, and these two types of traps are connected in parallel. By doing so, there is an advantage that the resonant frequency of a trap having the same electrode area and its neighboring frequency range can be wrapped at the same time.

[Invention or problem to be solved]

However, although using two types of traps as described above can reduce costs and board area compared to using three traps, it is still necessary to connect them to the circuit board separately. Therefore, it is not possible to achieve significant cost reduction and reduction of board area. In particular, when mounting on a circuit board, two types of traps with different trap characteristics must be connected in parallel, which may require strict component management.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a composite trap that traps a certain frequency and its neighboring frequency range with a single component, thereby reducing costs, occupying a board area, and simplifying component management.

[Means to solve the problem]

To achieve the above object, the first invention includes a first trap element made of a dual mode ceramic resonator having the same resonant frequency, and a second trap element made of a dual mode ceramic resonator having different resonant frequencies. , including a base with three glue-1 terminals protruding from one side edge in parallel,
The input electrode, ground electrode, and output electrode of the first trap element and the input electrode, ground electrode, and output electrode of the second trap element are connected to each lead terminal via lead electrodes formed on the base, respectively. It is characterized in that the periphery of the base, including a portion of the terminal, is sealed with an exterior resin.

Further, the second invention includes a first trap element consisting of a dual mode ceramic resonator having the same resonance frequency, a second trap element consisting of a dual mode ceramic resonator having different resonance frequencies, and three leads. a first terminal;
The input electrode, ground electrode, and output electrode of the trap element and the input electrode, ground electrode, and output electrode of the second trap element are respectively connected and fixed to the lead terminal, and the periphery of both trap elements including a part of the lead terminal is It is characterized by being sealed with an exterior resin.

[Effect]

In the case of a trap element consisting of a dual-mode ceramic resonator, if the areas of the vibrating electrodes are the same, the trap band will be narrow or the trap characteristics will be large, and if the area of the vibrating electrodes is different, the attenuation will be slightly smaller. or trap band or wide trap characteristics. By connecting these two types of traps in parallel, not only the main frequency but also the other two frequencies can be trapped simultaneously. In particular, the first
In the invention, two trap elements are fixed on one base, and three upper terminals are provided to protrude from the base, thereby forming a single component. Therefore, when mounting on a circuit board, it is possible to reduce the area occupied by the board, simplify component management, and eliminate the trouble of connecting REIT terminals to individual trap elements and applying an exterior, which significantly reduces manufacturing costs. can be reduced to

On the other hand, in the second invention, the base is omitted and the two trap elements are directly fixed to the lead terminals. Solder, conductive adhesive, or the like is used to secure the connection between the trap element and the terminal. In this case, since no base is required, there is an advantage that the parts can be made smaller.

〔Example〕

FIG. 1 shows a first embodiment of a composite trap according to the invention.

The base l is made of, for example, a printed circuit board, and lead electrodes 2, 3.4 are printed and wired in advance on one side of the base l. The above-mentioned drawn-out electric current ff12 drawn out to one side edge of the base l,
One end of three gate terminals 5, 6.7 is connected and fixed to the end of 3.4 by means of soldering 30 or the like.

Also, on the base 1 are first and second trap elements A and B.
are connected and fixed in parallel.

The first trap element A is composed of an energy-trapped dual-mode ceramic resonator that utilizes a thickness-shear vibration mode. On the whole surface of the rectangular piezoelectric ceramic substrate 10, as shown in FIG. 2a, there are input vibrating electrodes 1 having the same area.
1 and output vibrating electrodes 12 are formed at a certain interval, and these vibrating electrodes 11.1 and 12 are formed at both ends. Input terminal electrode 13 and output terminal electrode 14 respectively drawn out from +2
is formed.

On the other main surface of the piezoelectric ceramic substrate 10, as shown in FIG. 2b, there are vibrating electrodes 15 and 16 facing the vibrating electrodes I+ and 12.
A grounding terminal electrode 17 is formed in the center thereof. The resonant frequency of the first trap element A is, for example, 4.5M.
H, and as shown in FIG. 3, the trap band is narrow but the attenuation is large.

On the other hand, the second trap element B is also made of an energy-trapping type dual-mode ceramic resonator that utilizes the thickness-shear vibration mode. Strip-shaped piezoelectric ceramic substrate 20
As shown in FIG. 4a, an input vibrating electrode 21 and an output vibrating electrode 22 with different areas are formed at regular intervals on the whole surface of the holder, and a vibrating electrode 21 and an output vibrating electrode 22 are formed at both ends thereof, respectively. An input terminal electrode 23 and an output terminal electrode 24 are formed. Piezoelectric ceramic substrate 20
The other main surface is provided with the vibrating electrode 21.2 as shown in Fig. 4b.
Vibration electrodes 25, 26 and a grounding terminal electrode 27 are formed opposite to the electrode 2. The resonant frequency of the second trap element B is, for example, 4.8 MH! and 5.05 MH, and as shown in FIG. 5, the attenuation amount is somewhat small and the trap band exhibits characteristics that are wide.

In the case of a trap element made of a ceramic resonator, the resonant frequency is determined by the electrode area and the thickness of the piezoelectric ceramic substrate, and the smaller the electrode area and the thinner the piezoelectric ceramic substrate, the higher the resonant frequency. For example, the first. When piezoelectric ceramic substrates 10°20 with the same width W and the same thickness are used as the second trap elements A and B, the width dimension d of each vibrating electrode 11.12 and 21.22 is required to obtain the above resonance frequency. +, dx.

d may be set as follows.

dl >d, >d3 Input terminal electrode 13 of first trap element A. The ground terminal electrode 17, the output terminal electrode 14, and the input terminal electrode 23 of the second trap element B. The grounding terminal electrode 27 and the output terminal electrode 24 are connected to the extraction electrodes 2, 3.4 formed on the base 1, respectively, with a conductive paste 31 or the like, and are mechanically fixed at the same time. Thereafter, the periphery of the base 1 is dip-coated with a rubber-like elastic body 40 such as silicone rubber, and the periphery thereof is further dip-coated with an exterior resin 50 such as epoxy resin to obtain a composite trap. Note that the rubber-like elastic body 40 is the trap element A.

The purpose is to damp the thickness shear vibration generated in B to a certain extent to suppress spurious vibrations, and to alleviate the molding shrinkage force of the exterior resin 50, and it is sufficient that it covers at least the surroundings of the trap elements A and B. It is not necessary to cover the entire base 1.

FIG. 6 is an equivalent circuit diagram of the composite trap configured as described above, and FIG. 7 shows the trap characteristics of the composite trap. As is clear from the figure, 4°5 MHl results in a large amount of attenuation, 4.8MH! and 5.0511+,
I understand that it can be trapped up to a certain level. Therefore, it is possible to reliably remove 4.5MHz audio signals that interfere with video signals, and also to
H. Nearby interference signals can also be removed.

FIGS. 8 and 9 show a second embodiment of the composite trap, and the same parts as in the first embodiment are given the same reference numerals and their explanations will be omitted.

In this embodiment, the head 60a of the input/output lead terminal 60.62 at both ends of the three lead terminals 60, 61, 62 is
.

62a is formed into a flat plate shape, and the head 61a of the center grounding lead terminal 61 is formed into a bifurcated shape. And the head 608.6 of the input/output lead terminal 60.62
Input terminal electrode 1 of the first trap element A with 2a in between.
3 and the output terminal electrode 14 and the input terminal electrode 23 and the output terminal electrode 24 of the second trap element B are connected and fixed by soldering or the like. Furthermore, the center portions of the two trap elements A and B are inserted between the bifurcated head 61a of the center grounding lead terminal 61, and the grounding terminal electrode 17.27 on the outer surface is inserted between the bifurcated head 61a. 6] It may be connected and fixed to the inner surface of a by soldering or the like. Thereafter, a composite trap is obtained by dip-coating the periphery of the trap elements A and B with a rubber-like elastic body 70 such as 7-recon rubber and an exterior resin 80 such as evokino resin.

The equivalent circuit and trap characteristics of the above composite trap are shown in the sixth section.
It is similar to FIG. 7 and FIG. This embodiment does not require a composite trap or base, and the two trap elements A and B are arranged laterally in parallel, allowing for smaller parts and
There is a feature that makes it possible to lower the height.

In the composite trap of the second embodiment, the shape of the lead terminal is not limited to that shown in the drawings, and trap elements A and B may be arranged in parallel in the vertical direction, for example.

The present invention is not limited to trap elements shaped like those in the embodiments.
Furthermore, the present invention is not limited to a ceramic resonator that utilizes a thickness-shear vibration moat, but a ceramic resonator that utilizes a thickness-longitudinal vibration moat may also be used.

〔Effect of the invention〕

As is clear from the above explanation, according to the first invention, the first trap element is composed of a dual mode ceramic resonator having the same resonance frequency, and the second trap element is composed of a dual mode ceramic resonator having a different resonance frequency. Since the trap elements are connected in parallel, it is possible to trap not only the main frequency but also the nearby frequency range at the same time. Moreover, two tigers,
By fixing the pull-up element on a single base and protruding three terminals from the base, it is constructed as a single electronic component, which reduces the area occupied by the board when mounted on a circuit board. At the same time, parts management becomes easier and manufacturing costs can be significantly reduced.

In addition, in the second invention, the base is omitted and two tigers,
Since the bus element is directly fixed to the lead terminal, in addition to the first effect, there is an advantage that the components can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a first embodiment of the composite trap according to the present invention, FIGS. 2a and 2b are front and rear views of the first trap element, and FIG. 3 is a trap characteristic diagram of the first trap element. , Figures 4a and 4b are front and rear views of the second trap element, Figure 5 is a trap characteristic diagram of the second trap element, Figure 6 is an equivalent circuit diagram of the composite trap, and Figure 7 is the composite trap. Fig. 8 is a perspective view of a second embodiment of the composite trap, and Fig. 9 is an exploded perspective view thereof. A. 1st trap element, B. 21st wrap element, l
...Base, 2-4...Leader electrode, 5-7-Leat terminal, ]], ]2. +5.16.21.22.25.26
... Vibrating electrode, 13°] 4.17.23.24.27
- Terminal electrode, 40.70 - Rubber-like elastic body, 50. go
・Exterior resin, 60-62...Lead terminal. Figure 1 Figure 6 Figure 7■ Figure 9

Claims (1)

[Claims] (1) A trap for removing a specific frequency signal contained in a signal, which includes a first trap element made of a dual-mode ceramic resonator with the same resonant frequency, and a dual-mode ceramic resonator with different resonant frequencies. a second trap element consisting of a resonator;
A base having three lead terminals protruding in parallel from one side edge, and an input electrode, a ground electrode, and an output electrode of the first trap element, and an input electrode, a ground electrode, and an output electrode of the second trap element. is connected to each lead terminal via an extraction electrode formed on the base, and the periphery of the base including a part of the lead terminal is sealed with an exterior resin. (2) A trap for removing a specific frequency signal contained in a signal, the first trap element consisting of a dual mode ceramic resonator with the same resonance frequency and the dual mode ceramic resonator with different resonance frequencies. a second trap element consisting of a resonator;
The input electrode, the ground electrode, and the output electrode of the first trap element, and the input electrode, the ground electrode, and the output electrode of the second trap element are respectively connected and fixed to the lead terminals, and the lead terminals A composite trap characterized in that the peripheries of both trap elements, including a part of the trap elements, are sealed with an exterior resin.