JPH04217108A - Chip-shaped piezoelectric equipment - Google Patents

Abstract

PURPOSE:To improve a characteristic as the piezoelectric equipment and to secure the high characteristic as the piezoelectric equipment by arranging an electrode for input and an electrode for output through an intermediate substrate. CONSTITUTION:An electrode 9a for input and an electrode 9b for output are arranged through an intermediate substrate 2 so as not to be faced each other, no large stray capacity is formed between them, and an attenuating amount is prevented from being lowered at a certain part excepting for the passing band of a filter. On the other hand, one of counter electrodes 3a and 3b of respective piezoelectric resonators is pulled out to the short side end part of a piezoelectric substrate 3, and the other one is pulled to the long side end part. Then, the piezoelectric resonators are arranged so as to invert the respective pulled-out parts, short side pulled-out parts 4a and 4b are connected to the electrodes 9a and 9b, and the long side pulled-out parts 4a and 4b are electrically connected by a repeating electrode 8. Thus, the electrodes 9a and 9b can be easily and securely arranged at certain positions through the intermediate substrate 2 so as not to be faced each other.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to piezoelectric components, and more particularly to chip-type piezoelectric components such as filters and traps using piezoelectric resonators.

0002

2. Description of the Related Art As a conventional chip-type piezoelectric component, there is, for example, a chip-type piezoelectric filter whose cross section is shown in FIG. This chip-type piezoelectric filter is formed by laminating two piezoelectric resonators 51a and 51b with an intermediate substrate 52 in between, and further laminating protective substrates 57a and 57b on the outside thereof. These piezoelectric resonators 51a, 51b have a structure as shown in FIGS. 8 and 9, and one main surface of the piezoelectric substrate 53 has opposing electrodes 53a, 5
3b is formed, from which an input extraction electrode 54a and an output extraction electrode 54b are extracted from both ends. Further, on the other surface of the piezoelectric substrate 53, a common electrode 55 and a grounding electrode 56a (56b) drawn out from the common electrode 55 are provided.
is formed. Both piezoelectric resonators 51a and 51b have the same shape, and the electrode patterns formed on both surfaces thereof are also the same. As shown in FIG. 7, the output extraction electrode 54b of the piezoelectric resonator 51a is connected to the input extraction electrode 54a of the piezoelectric resonator 51b via a relay electrode 58 formed on the end surface side of the middle substrate 52. has been done. Furthermore, a protective substrate 5 is provided on the outside of the piezoelectric resonators 51a and 51b.
7a, 57b are stacked, and the protective substrates 57a, 57
An input electrode 59a that connects to the input extraction electrode 54a of the piezoelectric resonator 51a and an output electrode 59b that connects to the output extraction electrode 54b of the piezoelectric resonator 51b are formed at the same end of the piezoelectric resonator 51a. . Furthermore, the protective substrate 57a,
Grounding electrodes 60a and 60b are formed at the end of 57b on which the electrodes 59a and 59b are not formed, to be connected to the grounding lead-out electrodes 56a and 56b. Note that 61 is a filler made of an elastic material (such as silicone rubber) for absorbing unnecessary vibrations. in this way,
In this chip-type piezoelectric component, two piezoelectric resonators are stacked via the middle substrate 52 and connected to each other, thereby forming multiple pairs of opposing electrode parts on one long piezoelectric substrate, as in the past. A filter with an equivalent circuit equivalent to that of the original is constructed, and its size is reduced.

0003

However, in the conventional chip-type piezoelectric filter described above, the input electrode 59a and the output electrode 59b are arranged on the same end side, and are mutually connected to each other via the middle substrate 52. Since they are opposed to each other, there is a problem that stray capacitance tends to occur in the opposed portions, and the amount of attenuation becomes small in terms of filter characteristics, making it impossible to necessarily obtain sufficient filter characteristics. Further, this problem is not limited to piezoelectric filters, but also occurs in discriminators and other piezoelectric components.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a chip-type piezoelectric component that is difficult to form stray capacitance and has excellent piezoelectric properties such as filter properties.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the chip-type piezoelectric component of the present invention is provided with a pair of opposing electrodes on one surface of a piezoelectric substrate and a common electrode on the other surface. a plurality of piezoelectric resonators formed and laminated with an intermediate substrate interposed therebetween; a protective substrate laminated on the outside of the piezoelectric resonator; and an input electrode and an output electrode that are electrically connected to a counter electrode of the piezoelectric resonator. A piezoelectric component, comprising: a piezoelectric component in which opposing electrodes of each of the piezoelectric resonators are connected by a relay electrode, wherein the input electrode and the output electrode do not face each other via the intermediate substrate, and They are characterized by being arranged at considerable intervals.

[0006] Furthermore, the chip type piezoelectric component of the present invention has two
One of the opposing electrodes of each piezoelectric resonator is drawn out to the short side end of the piezoelectric substrate, and the other is drawn out to the long side end of the piezoelectric substrate, and the short side drawn out portions are on opposite sides. Each piezoelectric resonator is arranged so that the long side drawn out part is located on the same side as the long side drawn out part of the other piezoelectric resonator, and the short side drawn out part is used as the input/output part. By electrically connecting the long-side drawn-out portions of each piezoelectric resonator to the electrodes through the relay electrodes, the input electrodes and the output electrodes do not have to face each other through the middle substrate. , and are arranged at considerable intervals.

[0007]

[Function] Since the input electrode and the output electrode are arranged at a considerable distance from each other without facing each other through the middle substrate, a large stray capacitance is not formed between them. Adverse effects on piezoelectric properties are suppressed. For example, when the chip-type piezoelectric component is a filter, the characteristics as a piezoelectric filter are improved, such as ensuring high filter performance without reducing the amount of attenuation outside the passband.

[0008] Furthermore, one of the opposing electrodes of each piezoelectric resonator is drawn out to the short side end of the piezoelectric substrate, and the other is drawn out to the long side end, and the short side drawn out portions are located on opposite sides. , each piezoelectric resonator is arranged so that the long side drawn out part is located on the same side as the long side drawn out part of the other piezoelectric resonator, and the short side drawn out part is connected to the input/output electrode. And,
By electrically connecting the long-side drawn-out portions of each piezoelectric resonator with the relay electrode, it becomes possible to easily and reliably arrange the input and output electrodes at positions where they do not face each other with the middle substrate interposed therebetween.

[0009]

[Example] Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is an exploded perspective view showing a chip-type piezoelectric filter according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a filter element constituting the piezoelectric filter, and FIG. 3 is a perspective view showing the surface side of the filter element. , FIG. 4 is a perspective view showing the back side thereof. As shown in FIG. 2, etc., the filter element A of the chip-type piezoelectric filter includes two piezoelectric resonators 1a and 1b stacked together with an inner substrate 2 interposed therebetween, and protective substrates 7a and 7b further stacked on the outside thereof. It is formed by The piezoelectric resonators 1a and 1b have a structure as shown in FIGS. 5 and 6, both principal surfaces of which are shown in FIGS. For example, to explain the structure of the piezoelectric resonator 1b, opposing electrodes 3a and 3b are formed on one main surface of the piezoelectric substrate 3.
An output extraction electrode 4a is drawn out from one counter electrode 3a to the short side end of the piezoelectric substrate 3, and an output lead electrode 4a is drawn out from the other counter electrode 3b to the upper end of the long side of the piezoelectric substrate 3 (input ) The extraction electrode 4b is extracted. In addition, the piezoelectric substrate 3
A common electrode 5 and a grounding electrode 6 extending from the common electrode 5 to the lower end of the longer side are formed on the other surface of the common electrode 5 . The structure of the other piezoelectric resonator 1a is also the same as that of the piezoelectric resonator 1b, and the two piezoelectric resonators 1a and 1b are arranged so that the positions of the extraction electrodes 4a on the short side are opposite (diagonal arrangement). For example, the surfaces on which the common electrode 5 is formed are placed facing each other)
Then, the left and right positions of the extraction electrodes 4b on the long side are also reversed (diagonal arrangement). In the above filter element A, the long side (output) extraction electrode 4 of the piezoelectric resonator 1a
b is connected to the long side (for input) of the other piezoelectric resonator 1b via a relay electrode 8 formed by vapor-depositing an electrode material.
It is connected to the extraction electrode 4a. Further, the grounding lead electrodes 6, 6 of each piezoelectric resonator 1a, 1b are connected to relay electrodes 14 formed by vapor deposition on the back surface of the filter element A.
are connected to each other by A piezoelectric resonator 1a is mounted on one end side of the filter element A laminated and configured in this way.
An input connection electrode 10a is connected to the short side (input) extraction electrode 4a of the piezoelectric resonator 1b, and an output connection electrode 10b is connected to the short side (output) extraction electrode 4b of the piezoelectric resonator 1b at the other end. is formed by a method such as vapor deposition or sputtering. Then, this filter element A is sealed with sealing substrates 12 and 13 having recesses 14, and input electrodes 9a connected to the input connection electrodes 10a are provided at both ends thereof.
An output electrode 9b is formed to be connected to the output connection electrode 10b. Furthermore, the input/output electrodes 9a, 9b
A grounding electrode 11 connected to the grounding lead-out electrodes 6, 6 is formed between them.

In the chip-type piezoelectric filter constructed in this way, the input electrode 9a and the output electrode 9b are arranged so as not to face each other with the middle substrate 2 in between, and there is a gap between them. Since large stray capacitance is not formed, it is possible to prevent the attenuation of the portion outside the passband of the filter from decreasing. In addition, the counter electrode 3a of each piezoelectric resonator
, 3b is drawn out to the short side end of the piezoelectric substrate 3, and the other is drawn out to the long side end, and the piezoelectric resonators are arranged so that each drawn out part is oriented in the opposite direction, and the short side drawn out part 4a, 4a to the input electrode 9a and output electrode 9b, and electrically connect the long side drawn-out portions 4b, 4b with the relay electrode 8, the input/output electrodes 9a, 4a can be easily and reliably connected. 9b can be arranged at positions that do not face each other with the middle substrate 2 interposed therebetween. In addition, when an experiment was conducted on the chip-type piezoelectric filter according to the example, the result was 4.5.
Approximately 9 dB improvement was observed in spurious attenuation below MHz.

Note that the opposing electrodes 3a, 3b formed on the piezoelectric resonators 1a, 1b and the input/output lead electrodes 4a, 4b drawn out from them, or the common electrode 5 and the grounding lead drawn out from them. The shape of the electrode 6, its positional relationship, etc. are not limited to the above-mentioned embodiment, and can be arbitrarily changed without reducing the effects of the present invention.

[0012] The same applies to the shapes and arrangement positions of the input and output electrodes 9a, 9b and the connection electrodes 10a, 10b therefor, and the above embodiments are not intended to limit the scope of the present invention in any way. . Therefore, for example,
It is also possible to form the input/output electrodes 9a, 9b on the end face side of the filter element A, and in this case, the input/output electrodes can be formed after the chip-type piezoelectric filter is assembled into its final shape.

Furthermore, in the above embodiment, the long side (output) extraction electrode 4b of the piezoelectric resonator 1a and the other piezoelectric resonator 1
A case has been described in which the relay electrode 8 that connects the long side (input) extraction electrode 4b is formed by vapor deposition, but the relay electrode 8 can be formed by sputtering or applying a conductive paste.
It can be formed by various methods such as baking. However, if the relay electrode 8 is formed by applying and baking a conductive paste, there is a risk that the damping effect of the conductive paste may cause variations in the characteristics of the product. Preferably, electrode 8 is formed.

In the above embodiment, a chip-type piezoelectric filter has been described, but the present invention is not limited to this, and can be applied to discriminators, traps, etc. in addition to filters.

[0015]

[Effects of the Invention] As described above, in the chip-type piezoelectric component of the present invention, the input electrode and the output electrode are arranged at a considerable distance from each other without facing each other across the intermediate substrate. Therefore, large stray capacitance is not formed between the two, making it possible to improve the characteristics of the piezoelectric component. For example, when the piezoelectric component is a filter, it is possible to It is possible to ensure high characteristics as a piezoelectric filter, such as no reduction in the amount of attenuation in the piezoelectric filter.

[0016] Also, one of the opposing electrodes of each piezoelectric resonator is drawn out to the short side end of the piezoelectric substrate 3, and the other is drawn out to the long side end, and piezoelectric resonance is performed so that each drawn out part is oriented in the opposite direction. By arranging the short side lead-out portions to the input and output electrodes, and electrically connecting the long side lead-out portions to the relay electrodes 8, the input and output electrodes can be easily and reliably connected to the input and output electrodes. They can be arranged at positions that do not face each other with the substrate interposed therebetween.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing a chip-type piezoelectric filter according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a filter element constituting the chip-type piezoelectric filter of FIG. 1;

FIG. 3 is a perspective view showing the structure of the front side of the assembled filter element.

FIG. 4 is a perspective view showing the structure of the back side of the assembled filter element.

5 is a front view showing the structure of the front side of a piezoelectric resonator used in a filter element constituting the chip-type piezoelectric filter of FIG. 1. FIG.

6 is a front view showing the structure of the back side of a piezoelectric resonator used in a filter element constituting the chip-type piezoelectric filter of FIG. 1. FIG.

FIG. 7 is a cross-sectional view showing a conventional chip-type piezoelectric filter.

FIG. 8 is a front view showing the structure of the front side of a piezoelectric resonator used in a conventional chip-type piezoelectric filter.

FIG. 9 is a front view showing the structure of the back side of a piezoelectric resonator used in a conventional chip-type piezoelectric filter.

[Explanation of symbols]

1a, 1b piezoelectric resonator 2
Middle board 3
Piezoelectric substrates 3a, 3b counter electrodes

Claims (2)

[Claims] 1. A plurality of piezoelectric resonators formed by providing a pair of opposing electrodes on one surface of a piezoelectric substrate and providing a common electrode on the other surface, and stacked with an intermediate substrate interposed therebetween, and the piezoelectric resonators a protective substrate laminated on the outside of the piezoelectric resonator, and an input electrode and an output electrode that are electrically connected to the opposing electrode of the piezoelectric resonator, and the opposing electrode of each piezoelectric resonator is connected by a relay electrode. A chip-type piezoelectric component, characterized in that the input electrode and the output electrode do not face each other with the intermediate substrate interposed therebetween, and are arranged at a considerable interval. 2. Using two piezoelectric resonators, one of the opposing electrodes of each piezoelectric resonator is drawn out to the short side end of the piezoelectric substrate, and the other is drawn out to the long side end of the piezoelectric substrate, and the short side drawn out. Each piezoelectric resonator is arranged such that the long side drawn out portion is located on the same side as the long side drawn out portion of the other piezoelectric resonator, and the short side By connecting the lead-out portion to the input/output electrode and electrically connecting the long-side lead-out portion to the relay electrode, the input electrode and the output electrode are opposed to each other with the middle substrate interposed therebetween. 2. The chip-type piezoelectric component according to claim 1, wherein the chip-type piezoelectric component is arranged at a considerable interval without any problem.