JPS62221211A - Ceramic resonator - Google Patents

Abstract

PURPOSE:To attain plural resonance frequencies and realize a trap for sound intermediate frequency (SIF) signal and an element for multiple mode group delay equalizer by connecting one of divided electrodes on one face of a piezoelectric ceramic substrate and a common electrode on the other face facing said divided electrodes. CONSTITUTION:A pair of divided electrodes 2 and 3 are arranged with a gap g1 between them on one face of a rectangular plane plate-shaped piezoelectric ceramic substrate 1, and a common electrode 4 facing them is provided on the other face. Output terminals 6 and 7 are provided for lead electrodes 21 and 31 extended from divided electrodes 3 and 4, and one lead electrode 31 and a lead electrode 41 extended from the common electrode 4 are connected by a conductor 5. Thus, this ceramic resonator has two resonance frequencies and two antiresonance frequencies and is used not only as a ceramic trap element for SIF signal or the like but also for a multiple mode group delay equalizer or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention forms a pair of divided electrodes on one side of a piezoelectric ceramic substrate in the thickness direction, and a common electrode facing the pair of divided electrodes on the other side. By connecting one of the divided electrodes and a common electrode in the formed multi-mode ceramic resonator.

It is designed to have multiple resonant frequencies.

2. Description of the Related Art This type of ceramic resonator is mainly used in television receivers to convert audio intermediate frequency (hereinafter referred to as SIF) contained in a video signal into video intermediate frequency (hereinafter referred to as PI).
Ceramic tora-2 to be separated and removed from (referred to as F)
Used as a pull-up element. FIG. 18 is a diagram showing the structure of a conventional ceramic resonator of this type, and FIG. 19 is an equivalent circuit diagram thereof. In FIG. 18, 1 is a piezoelectric ceramic substrate, 2 and 3 are a pair of divided electrodes formed on one side of the piezoelectric ceramic substrate 1 in the thickness direction, and 4 is a pair of divided electrodes formed on the other side of the piezoelectric ceramic substrate 1. This is a common electrode formed to face electrode 2.3.

When the above ceramic resonator is used as a four-terminal circuit element by connecting the terminals a to d to the divided electrodes 2.3 and the common electrode 4, the ceramic resonator has a symmetrical mode (a) and an obliquely symmetrical mode (b). Operates in electric vibration mode.

The above ceramic resonator is connected to the S
When used as a ceramic trap element for removing IF signals, the resonant frequency fr is set to 4.5 MH2 since the SIF signal is 4.5 MHz. Figure 20 shows a trap characteristic diagram when the ceramic resonator shown in Figure 18 is used as a ceramic trap element, with the horizontal axis representing frequency (MHz) and the vertical axis representing trap amount (dB).
As shown in this characteristic diagram, the frequency is 4.5.
Since the amount of trapping increases rapidly at MHz, the SIF signal is trapped.

Problems to be Solved by the Invention However, the conventional ceramic resonator shown in FIG. 18 has only one resonant frequency fr and one anti-resonant frequency fa, as shown in FIG. 20. For this reason, although it is effective as a ceramic trap element for removing SIF signals in television receivers, it cannot be used in applications such as multimode group delay equalizers, and its range of applications is narrow.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the present invention provides a ceramic resonator in which a pair of divided electrodes and a common electrode are arranged facing each other on both sides of a piezoelectric ceramic substrate. It is characterized in that one of the divided electrodes and the common electrode are connected.

Function: In the ceramic resonator according to the present invention, one of the pair of divided electrodes
Since the two electrodes are connected to the common electrode, a plurality of resonance frequencies can be provided.

Therefore, it can be used not only as a ceramic trap element for SIF signals, but also as a multimode group delay equalizer, and the range of applications is significantly expanded.

Embodiment FIG. 1 is a symbol diagram of a ceramic resonator according to the present invention. In FIG. 9, l is a piezoelectric ceramic substrate, 2 and 3 are
4 is a pair of divided electrodes formed on one side of the piezoelectric ceramic substrate l in the thickness direction, and 4 is the piezoelectric ceramic substrate l.
This is a common electrode formed on the other side so as to face the pair of divided electrodes 2.3. A significant difference from the conventional method is that one of the pair of divided electrodes 2.3, for example, divided electrode 3, is directly connected to common electrode 4 by conductive wire 5. 6
is a terminal connected to the divided electrode 2, and 7 is a terminal drawn out from the common electrode.

ff52 is an equivalent circuit diagram of the ceramic resonator shown in FIG. 1, and FIG. 3 is a frequency attenuation characteristic diagram.

As shown in FIG. 3, the ceramic resonator shown in FIG. 1 has two resonance frequencies, frequency Frs and frequency Fra.
The resonance frequencies Frs and Fra, which have two anti-resonance frequencies, the frequency Fax and the frequency Faa, are expressed by the following equation using the equivalent circuit shown in FIG.

F rs = l / 2 πrLs, CsF ra =
1/2 πrLa, Ca Therefore, Ls, C
2 by selecting circuit constants such as s, La, Ca, etc.
A ceramic trap element with two trap frequencies,
A multi-mode group delay equalizer, etc. can be realized.

FIG. 4 is a plan view showing the specific structure of the ceramic resonator shown in FIG. 1, FIG. 5 is a side view of the resonator, and FIG. 6 is a bottom view. In this embodiment, a pair of divided electrodes 2.3 are arranged facing each other across a gap g1 on one surface side in the plate thickness direction of a piezoelectric ceramic substrate l formed in a rectangular flat plate shape, and a pair of divided electrodes 2.3 are arranged facing each other with a gap g1 therebetween. A common electrode 4 facing the divided electrodes 2 and 3 is provided, and a lead electrode 31 is extended from the divided electrode 3.
and a lead electrode 41 extending from the common electrode 4 are electrically connected by a conductive wire 5, and a lead terminal 6 is connected to the lead electrode 21 extending from the 0-divided electrode 2. The lead terminal 7 is connected to the lead electrode 31 of the divided electrode 3 which is connected to the lead electrode 41 by the conducting wire 5.

FIG. 7 is a symbol diagram in another embodiment. In this embodiment, the divided electrode 3 and the common electrode 4 are connected to a capacitor C
Connect via . Also in the case of this embodiment, a ceramic resonator having two resonance frequencies Frs and Fra can be obtained.

FIG. 8 is a plan view showing the specific structure of the ceramic resonator shown in FIG. 7, and FIG. 9 is a bottom view of the ceramic resonator shown in FIG. Although not shown, a resistor may be inserted in place of the capacitor C.

FIGS. 1θ to 15 show other embodiments of the ceramic resonator according to the present invention.

First, in the symbol diagram of the ilO diagram, the circuit configuration is a combination of two resonators A and B. Resonator A is
A pair of divided electrodes 2A on one side of the piezoelectric ceramic substrate IA
, 3A, and divided electrodes 2A, 3A on the other side.
The resonator B also has a pair of divided electrodes 2B and 3B formed on one side of the piezoelectric ceramic substrate IB, and a pair of divided electrodes 2B and 3B on the other side. A common electrode 4B facing each other is provided. The divided electrodes 3A and 3B of the resonators A and H are commonly connected to the common electrodes 4A and 4B by a conductive wire 5. A lead terminal 6 is connected to the split electrode 2A of the resonator A.
A is connected to the resonator B, and a lead terminal 6B is connected to the divided electrode 2B of the resonator B.

To obtain a ceramic resonator as shown in the symbol diagram of FIG. 10, two ceramic resonators having the configuration shown in FIG. 1 may be combined, but as shown in FIGS. 11 and 12, In addition, forming the ceramic resonators A and B using the same piezoelectric ceramic substrate L is an effective way to reduce the size of the element.
This is advantageous in terms of cost reduction and ease of use. In FIGS. 11 and 12, a piezoelectric ceramic substrate 1 formed in a rectangular flat plate shape is used, and a pair of divided electrodes 2A, 3A and a common electrode 4A constituting a resonator A are provided near one end of the substrate. The structure is such that split electrodes 2B, 3B and a common electrode 4B forming the resonator B are provided at an appropriate distance from the resonator A portion. Split electrode 3 of resonator A
A and the divided electrode 3B of the resonator B are commonly connected by a lead electrode 32, and the common electrodes 4A and 4B are commonly connected by a lead electrode 42. A5 etc. are used for conductive connection. Then, the lead terminal 6A is connected to the lead electrode 21A extended from the divided electrode 2 of resonator A, the lead terminal 6B is connected to the lead electrode 21B extended from the divided electrode 2B of resonator B, and the lead terminal 6B is connected to the lead electrode 21A extended from the divided electrode 2 of resonator A. 32 is electrically connected to the lead terminal 7. Since the lead electrode 32 is electrically connected to the lead electrode 42 of the common electrodes 4A and 4B by the conductor 5, the lead terminal 7 may be electrically connected to the lead electrode 42.

Next, in the symbol diagram of Fig. 13, the combination of two resonators A and B is similar to the case of Fig. 1θ, but when connecting the divided electrodes 3A and 3B to the common electrodes 4A and 4B, , is different in that they are connected via a capacitor C.

14 and 15 show a specific example in which the ceramic resonator shown in FIG. 13 is formed using the same piezoelectric ceramic substrate l. In the embodiments of FIGS. 14 and 15, the same reference numerals as in FIGS. 11 and 12 indicate identical components. The capacitor C is generated by the overlapping area of the lead electrode 32 extended from the divided electrodes 3A, 3B and the lead electrode 42 extended from the common electrode 4A, 4B. Further, the lead terminal 7 is connected to the lead electrode 42.

Also in the embodiments shown in FIGS. 1O to 15, a ceramic resonator having two resonant frequencies Frs and Fra can be obtained.

FIG. 16 is a trap characteristic diagram of a ceramic resonator related to unfired Ill. This characteristic diagram was obtained with the circuit configuration shown in FIG. 17. In FIG. 17, a circuit is constructed by combining two ceramic resonators A and B having the configuration shown in FIG. 1.

As shown in the characteristic diagram of ft516, the resonance frequency Frs of 10.5MHz and the resonance frequency Frs of IO,7MHz.
a, and these two resonance frequencies F rs and F ra
A ceramic trap element is obtained that traps a frequency signal of .

As described in "2. Effects of the Invention", an unexplained problem is that in a ceramic resonator in which a pair of divided electrodes and a common electrode are arranged facing each other on both sides of a piezoelectric ceramic substrate, one of the pair of divided electrodes is
The ceramic is characterized in that it has a plurality of resonant frequencies and can be used not only as a ceramic trap element for SIF signals, but also for applications such as a multimode group delay equalizer. A resonator can be provided.

[Brief explanation of drawings]

FIG. 1 is a symbol diagram of a ceramic resonator according to the present invention,
Fig. 2 is an equivalent circuit diagram of the ceramic resonator shown in the ft51 diagram, Fig. 3 is a frequency attenuation characteristic diagram, and Fig. 4 is a plane showing the specific structure of the ceramic resonator shown in Fig. 1. figure,
FIG. 5 is a side view thereof, FIG. 6 is a bottom view, FIG. 7 is a symbol diagram of another embodiment, and FIG. 8 is a plan view showing the specific structure of the ceramic resonator shown in FIG. 7. , No. 9
The figure is a bottom view of the same, the 1θth figure is a symbol diagram of another embodiment, the figure 11 is a plan view showing the specific structure of the ceramic resonator shown in figure 10, and the figure 12 is a bottom view of the same. , FIG. 13 is a symbol diagram in another embodiment,
FIG. 14 is a plan view showing the specific structure of the ceramic resonator shown in FIG. 13, FIG. 15 is a bottom view thereof, FIG. 16 is a trap characteristic diagram of the ceramic resonator according to the present invention, and FIG. The figure is a circuit diagram used to obtain the trap characteristics shown in Figure 16, tJSla is a diagram showing the structure of a conventional ceramic resonator of this type, Figure 19 is its equivalent circuit diagram, and Figure 20 is It is a trap characteristic diagram when the ceramic resonator shown in the fjSla diagram is used as a ceramic trap element. 1, IA, IB...Piezoelectric ceramic substrate 2.3.2A
, 2B, 3A, 3B...Φ split electrode 4.4A, 4B@...
・Common electrode whistle 1p 221st 4th 1st 5t 1st 61z1 721st 80th 9th C4 1Q figure 1311th 161.1 17th! a Nodal circle [ㅅ; Figure 19

Claims (6)

[Claims] (1) A ceramic resonator in which a pair of divided electrodes and a common electrode are arranged facing each other on both sides of a piezoelectric ceramic substrate, characterized in that one of the pair of divided electrodes and the common electrode are connected. resonator. (2) The ceramic resonator according to claim 1, wherein one of the pair of divided electrodes and the common electrode are directly connected. (3) The ceramic resonator according to claim 1, wherein one of the pair of divided electrodes and the common electrode are connected via a capacitor. (4) The ceramic resonator according to claim 1, wherein one of the pair of divided electrodes and the common electrode are connected via a resistor. (5) Claims 1, 2, 3, or 4, characterized in that a plurality of resonators each consisting of the pair of divided electrodes and the common electrode are provided. The ceramic resonator described in . (6) Claim 5, characterized in that the plurality of resonators are formed on the same piezoelectric ceramic substrate.
Ceramic resonators as described in Section.