JP2666295B2 - Composite component of piezoelectric resonator and capacitor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a composite component in which a piezoelectric resonator and a capacitor are integrally formed. [Prior Art] Conventionally, an oscillation circuit using a piezoelectric resonator used as a component of a microprocessor or the like is generally a Colpitts oscillation circuit as shown in FIG. This circuit has a configuration in which both ends of a parallel circuit of a signal inverting inverter 1, a feedback resistor 2, and a piezoelectric vibrator 3 are grounded via load capacitors 4, 5, respectively. When such an oscillation circuit is mounted on a board together with, for example, a microprocessor chip, etc.
In FIG. 15, the piezoelectric resonator 3 and the capacitors 4 and 5 within the range surrounded by the broken line are separate components. For this reason, there is a problem in terms of management of each part at the time of manufacturing, securing of a mounting space on a board, reliability of electrical contact by soldering of parts, and the like. Under such circumstances, for example, the invention of Japanese Patent Application Laid-Open No. 60-123120 has been proposed. The present invention employs a configuration as shown in a vertical sectional view in FIG. 16, and specifically, a piezoelectric vibrator 101 and a dielectric substrate 102 for forming a load capacitor are formed in a case 100 by vibrating a space 103 for vibration. The ceramic oscillator having such a structure is arranged in spacers 104, 104 for forming and connecting the electrodes 105, and a ceramic oscillator having such a structure is disclosed in Japanese Utility Model Application Laid-Open No. 60-111115. 59-84922. [Problems to be Solved by the Invention] However, in such a configuration, the number of parts is still large, and the volume as a whole becomes large. There is a problem that becomes large. Further, a ceramic oscillator disclosed in Japanese Utility Model Application Laid-Open No.
Since the chip-shaped piezoelectric oscillator shown in Japanese Patent No. 922 has directionality in both the longitudinal direction and the thickness direction, it is necessary to pay attention to the directionality at the time of manufacturing and mounting on a substrate. In addition, there is a possibility that a mistake during manufacturing and a work mistake during mounting may occur. Further, there is a problem that the size of the input electrode and the output electrode is limited, so that a capacitor having a large capacity cannot be formed. The present invention has been made in view of such circumstances, and has as few components as possible, and its size, particularly its length, has been reduced. It is an object of the present invention to provide a composite component including a piezoelectric resonator and a capacitor. [Means for Solving the Problems] In the composite part of the piezoelectric resonator and the capacitor of the present invention,
A dielectric substrate is laminated on both sides of the piezoelectric vibrator with electrodes interposed therebetween, and the dielectric substrate also serves as a case. A composite component of a piezoelectric resonator and a capacitor according to the present invention includes a piezoelectric substrate, first and second internal electrodes formed on both surfaces of the piezoelectric substrate, and both surfaces of the piezoelectric substrate with the internal electrodes interposed. And a first and second dielectric substrate of the same shape and the same material, each having a vibration space formed on one surface facing the piezoelectric substrate, and the other of the first and second dielectric substrates. A first, a second, a third, and a fourth external electrode disposed on a surface thereof, wherein the first and second external electrodes are connected to the first and second internal electrodes, A piezoelectric resonator is formed by the substrate and the first and second internal electrodes, the first dielectric substrate, the third external electrode, the first internal electrode and the first external electrode Constitute a first capacitor with the second dielectric substrate, the fourth external electrode, and the second internal electrode and the second external electrode. Characterized in that have configured second capacitor. [Operation] In the present invention, the dielectric for a capacitor, which is a main component, also functions as a case, and furthermore, the electrode of the piezoelectric resonator also functions as the electrode of the capacitor. Since the entire small first and second dielectric substrates have the same shape and the same material, they can be laminated on the piezoelectric substrate without paying attention to the directionality. Since the first, second, third, and fourth external electrodes are provided on the other surfaces of the first and second dielectric substrates laminated on the piezoelectric substrate, the first and second dielectric substrates Either of them can be mounted on a substrate facing the substrate. Hereinafter, the present invention will be described in detail with reference to the drawings illustrating the embodiments. FIG. 1 is a longitudinal sectional view showing a basic sectional structure of a composite component of a piezoelectric resonator and a capacitor according to the present invention, and FIG. 2 is an external view thereof. This is shown in FIG. FIG. 3 is a perspective view of a piezoelectric substrate, and FIG. 4 is a perspective view of a dielectric substrate. In the figure, reference numeral 11 denotes a piezoelectric substrate, and dielectric substrates 12 and 13 are laminated on the upper and lower surfaces thereof, respectively, to form a laminate 20. Also, as shown in FIG. 1, first and second internal electrodes 25 and 26 are interposed between the piezoelectric substrate 11 and the dielectric substrates 12 and 13 as shown in FIG. These internal electrodes 25 and 26 extend from both ends in the longitudinal direction of the laminated body 20 to positions slightly over the center, respectively. As shown in FIGS. 1 and 4, the dielectric substrates 12 and 13 are provided with concave spaces, that is, vibration spaces 15 and 16 of the piezoelectric substrate 11, on the surface facing the piezoelectric substrate 11. . Cap-shaped first and second cap-shaped bottom plates are provided at both side ends of the laminated body 20 formed in a sandwich structure in which the dielectric substrates 12 and 13 are located on both sides of the piezoelectric substrate 11 as a center. External electrodes 21 and 22 are attached. Each of these external electrodes 21 and 22 has one of the first external electrodes 21 electrically connected to an internal electrode 25 interposed between the piezoelectric substrate 11 and the dielectric substrate 12 on the surface on the side of the laminate 20; The other second external electrode 22 is electrically connected to the internal electrode 26 interposed between the piezoelectric substrate 11 and the dielectric substrate 13 on the surface on the side of the laminate 20. Further, a band-shaped external electrode 23 serving as a third external electrode and a fourth external electrode is attached to the center of the laminated body 20 in the longitudinal direction so as to be wound around the outer periphery of the laminated body 20. . In the product of the present invention having the above-described basic configuration, the piezoelectric substrate 11 and the first and second internal electrodes 25 and 2 located on both side surfaces thereof are provided.
6 constitute the piezoelectric vibrator 3 shown in FIG. 15, and as schematically shown in FIG. 6, a first dielectric substrate 12 and external electrodes 23 and internal electrodes 25 located on both side surfaces thereof. The first capacitor 4 shown in FIG. 15 is composed of the second dielectric substrate 13 and the external electrodes 23 and the internal electrodes 26 located on both side surfaces thereof.
Each of the second capacitors 5 shown in the figure is configured. FIG. 5 shows an equivalent circuit diagram of the product of the present invention whose basic configuration is shown in FIG. 1 and FIG. The composite component of the piezoelectric resonator and the capacitor according to the present invention has the above-described configuration, and a detailed configuration thereof will be described below. FIG. 7 is a schematic diagram showing a configuration for further ensuring electrical contact between the internal electrodes 25 and 26 and the external electrodes 21 and 22. That is, in the example of FIG. 7, a cavity 30 is provided in the dielectric substrate 13 near the contact portion between the internal electrode 26 and the external electrode 22.
The inside is filled with a conductive paste. In the example shown in FIG. 8, the dielectric substrate 13 is slightly shorter in the longitudinal direction than the piezoelectric substrate 11, whereby the cavity 30 formed between the dielectric substrate 13 and the external electrode 22 is filled with a conductive paste. I have to do that. Note that a corner of the dielectric substrate 13 at a contact portion between the internal electrode 26 and the external electrode 22 of the piezoelectric substrate 11 may be chamfered, and a void may be filled with a conductive paste. By the way, when fixing the dielectric substrates 12 and 13 and the internal electrodes 25 and 26 with an adhesive, if the adhesive protrudes into the vibration spaces 15 and 16, the piezoelectric vibration characteristics of the piezoelectric substrate 11 deteriorate. Invite. FIG. 9 is a schematic view showing an example of a configuration aiming at avoiding such a situation. The dielectric substrate 12 (13)
Vibration space 15 (16) on the surface facing the internal electrode 25 (26)
A groove 32 is formed which is substantially parallel to the edge of. With such a configuration, even when the adhesive material 31 applied between the dielectric substrate 12 (13) and the internal electrode 25 (26) tries to flow toward the vibration spaces 15 and 16, the groove 32 is formed. It is fastened at. FIG. 10 is an explanatory diagram showing the elements of the capacitance value of the load capacitance of the capacitor constituted by the piezoelectric substrate 11 and the dielectric substrate 12, respectively. The load capacitance value of this capacitor is
25 (26), the area S of the external electrode 23 located outside the dielectric substrate 12 (13), the dielectric constant εs of the dielectric substrate 12 (13), its thickness t1, and the vibration space 15 ( It is determined by the thickness t2 of 16). However, in this case, as shown in FIG. 11, when considering the capacitance value C of the capacitor formed by the dielectric substrate 12, the capacitance value C ′ using the external electrode 23 and the internal electrode 26 as electrodes is considered.
Exists. Therefore, for example, as shown in FIG.
, The capacitance value C 'can be reduced to a negligible value by slightly shifting the position to a position near the end of the line. Finally, the attachment of the external electrodes 21 and 22 to the laminate 20 will be described. For example, as shown in FIG. 13, the external electrodes 21 and 22 are formed by laminating the piezoelectric substrate 11 and the dielectric substrates 12 and 13 with an adhesive or the like as shown in FIG. After applying the conductive paste 33 on the surface, the metallic external electrode 21
14 or simply apply a conductive paste 33 to the end face of the laminate 20 or perform plating, as shown in FIG. [Effects of the Invention] As described above, according to the present invention, it is possible to configure a composite component of a piezoelectric resonator and a capacitor with a smaller number of components compared to the related art, and it is possible to reduce the size. Become. Also,
Since the first and second dielectric substrates have the same shape and the same material, when laminating them on the piezoelectric substrate, it is not necessary to pay attention to the direction thereof, and the occurrence of manufacturing errors can be prevented. Furthermore, since the first, second, third, and fourth external electrodes are provided on the other surfaces of the first and second dielectric substrates laminated on the piezoelectric substrate, when the present invention is mounted on the substrate, In addition, any of the first and second dielectric substrates can be mounted so as to be opposed to the substrate, thereby preventing mounting errors when mounting on the substrate. Still further, a first capacitor is constituted by the first dielectric substrate, the third external electrode, the first internal electrode, and the first external electrode,
Since the second capacitor is constituted by the second dielectric substrate, the fourth outer electrode, the second inner electrode, and the second outer electrode, the first and second capacitors can be formed as capacitors having a large capacitance. And so on.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention, FIG. 1 is a longitudinal sectional view showing a basic structure of a product of the present invention, FIG. 2 to FIG. FIG. 5 is an equivalent circuit diagram of the product of the present invention, FIGS. 6 to 14 are schematic diagrams showing the detailed configuration of the product of the present invention, FIG. 15 is a circuit diagram of a general oscillation circuit, and FIG. FIG. 3 ... Piezoelectric vibrator, 4,5 ... Capacitor, 11 ... Piezoelectric substrate, 12,13 ... Dielectric substrate, 15,16 ... Vibration space, 21,2
2,23 …… External electrode, 25,26 …… Internal electrode

Claims (1)

(57) [Claims] A piezoelectric substrate; first and second internal electrodes formed on both surfaces of the piezoelectric substrate; and a vibration surface located on both surfaces of the piezoelectric substrate with the internal electrodes interposed therebetween and facing the piezoelectric substrate. First and second dielectric substrates having the same shape and the same material in which a space for use is formed; and first, second, third and third dielectric substrates arranged on the other surfaces of the first and second dielectric substrates.
A fourth external electrode, wherein the first and second external electrodes are connected to the first and second internal electrodes, and the piezoelectric substrate and the first and second internal electrodes form a piezoelectric element. A first capacitor is formed by the first dielectric substrate, the third external electrode, the first internal electrode, and the first external electrode; A dielectric substrate;
A composite component of a piezoelectric resonator and a capacitor, wherein the fourth external electrode, the second internal electrode, and the second external electrode constitute a second capacitor. 2. The composite component of a piezoelectric resonator and a capacitor according to claim 1, wherein the third external electrode and the fourth external electrode are electrically connected.