JPH0559956U - Piezoelectric parts with built-in capacitance - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a capacitor-embedded piezoelectric component having a thin thickness and a stable capacitance value. [Structure] Piezoelectric member 1 having vibrating electrodes 2 and 3 provided on the front and back surfaces
Are held by the holding members 5 and 7 from both sides. Further, the capacitive electrodes 11 to 15 and 17 to 21 are provided outside the holding members 5 and 7.
The capacitive members 10 and 16 provided on the front and back surfaces are arranged to form the vibration substrate 23. The sealing substrate 25 is vertically stacked with the vibrating substrate 23 interposed therebetween (the sealing substrate stacked on top is not shown in FIG. 4). Capacity member 1
Nos. 0 and 16 are thin and have a flat surface without irregularities, and the capacitive electrodes 11 to 15 and 17 to 21 are accurately arranged. Therefore, the capacitance formed in the capacitance members 10 and 16 has a stable value without variation.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thin capacitor built-in type piezoelectric component used for an oscillator of an IC card or the like.

[0002]

[Prior art and problems]

 It is necessary to reduce the thickness of piezoelectric components used for oscillators of IC cards. In this type of piezoelectric component, one vibrating substrate is composed of a piezoelectric member provided with vibrating electrodes on the front and back surfaces, and holding members that hold the piezoelectric member from both sides, and the vibrating substrate is further sealed. It is known that they are sandwiched between stop substrates and laminated. Conventionally, this piezoelectric component has been used as an oscillator of an IC card by combining it with a capacitor that is a separate component.

However, in this case, there are problems that the number of components becomes plural, the mounting space for the IC card becomes wide, and the complicated work such as soldering in the component mounting process increases. Therefore, it is conceivable that a capacitive electrode is provided on the holding member to form a capacitive built-in type piezoelectric component, but it is difficult to accurately dispose the capacitive electrode because the holding member has an uneven surface. The capacitance value of the capacitance electrode was varied, and a stable capacitance could not be obtained.

Therefore, an object of the present invention is to provide a thin capacitor built-in type piezoelectric component that can be used as an oscillator for an IC card and has a stable capacitance value.

[0005]

[Means and actions for solving the problem]

 In order to solve the above-mentioned problems, a capacitive-embedded piezoelectric component according to the present invention includes a piezoelectric member having vibrating electrodes on the front and back surfaces, a holding member for holding the piezoelectric member from both sides, and an external member arranged outside the holding member. A laminated structure having a sealed vibrating space in which one vibrating substrate is configured with the capacitive members provided on the front and back surfaces of the capacitive electrode, and the vibrating substrate is sandwiched by sealing substrates. Is characterized by.

With the above structure, since the piezoelectric component has the capacitive member in addition to the holding member, the holding member has the same function of holding the piezoelectric resonator from both sides as in the conventional case, while the capacitive member is The thickness of the capacitor electrode is thin, and the surface thereof is a flat surface without unevenness, and the capacitor electrode is accurately arranged. Therefore, the capacitance formed in this capacitance member is large and has a stable and stable value.

[0007]

【Example】

 Hereinafter, an embodiment of a piezoelectric component having a built-in capacitor according to the present invention will be described with reference to the accompanying drawings together with its manufacturing method. As shown in FIG. 1, mother substrate-shaped holding members 5 and 7 are arranged on both sides of the mother substrate-shaped piezoelectric member 1, and mother substrate-shaped capacitance members 10 and 16 are arranged outside them. The piezoelectric member 1 is provided with vibrating electrodes 2 and 3 on the front and back surfaces. The piezoelectric member 1 is made of a ceramic material such as PZT, and the vibrating electrodes 2 and 3 are made of Ag or the like. The holding members 5 and 7 are provided with vibration space forming recesses 6 and 8, respectively. Capacitance electrodes 11, 12, 13, 14, 15 and capacitance electrodes 17, 18, 19, 20, 21 are provided on the front and back surfaces of the capacitance members 10, 16, respectively. The capacitance members 10 and 16 are made of alumina or the like, and the capacitance electrodes 11 to 15 and 17 to 21 are made of Ag or the like.

Next, various mother board-shaped members 1, 5, 7, 10, 16 are integrally fixed to each other via an adhesive, and then cut along a cut line C1 shown by a two-dot chain line in FIG. And cut the slice horizontally. In this way, the vibration substrate 23 having a mother substrate shape as shown in FIG. 2 is obtained. On the upper surface of the vibrating substrate 23, the electrodes 2, 3, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21 provided on the members 1, 10, 16 and external electrodes 30, 31, which will be described later, Auxiliary electrodes 22a and 22b are provided to ensure electrical connection with 32. Mother substrate-shaped sealing substrates 25 are fixed to the upper and lower sides of the vibrating substrate 23 with an adhesive to form a laminated body having a sealed vibrating space. The sealing substrate 25 is provided with a concave portion 26 on the surface on which the vibration space is formed, and conductors 27, 28, 29 are provided on the surface on the opposite side. Further, the laminated body is cut in a vertical direction along a cutting line C2 shown by a chain double-dashed line in FIG. 2 to separate into a laminated body of a product size.

Next, the external electrodes 30, 31, 32 are provided on both ends and the center of the product-sized laminate by means of sputtering, vapor deposition, plating, or the like. At this time, the external electrodes 30, 31, 32 are formed so as to cover the conductors 27, 28, 29 provided on the sealing substrate 25, respectively. When the distance between the external electrodes 30, 31, 32 is narrow, a solder resist or the like is applied to the surface of the laminated body to prevent a short circuit between the electrodes.

FIG. 4 is a horizontal sectional view of the thus-capacitor-type piezoelectric component obtained. The piezoelectric component shown in FIG. 4 is separated from the front side portion of the laminated body shown in FIG. The piezoelectric member 1 is provided with vibrating electrodes 2 and 3 on the front and back surfaces. Energy confinement type thickness-shear vibration mode vibration occurs at the portions where the vibrating electrodes 2 and 3 face each other. The holding members 5 and 7 provided with the vibration space forming recesses 6 and 7 fix and hold the surface of the piezoelectric member 1 on which the vibrating electrodes 2 and 3 are formed from both sides with an adhesive. Furthermore, the capacity members 10 and 16 are fixed to the outside of the holding members 5 and 7 with an adhesive agent on the surface opposite to the surface of the holding members 5 and 6 where the recesses 6 and 7 are formed. .. Capacitance electrodes 11, 12, 13, 14, 15 and capacitance electrodes 17, 18, 19, 20, 21 are provided on the front and back surfaces of the capacitance members 10, 16, respectively.

In this way, the piezoelectric member 1, the holding members 5 and 7, and the capacitance members 10 and 16 form one vibration substrate 23. Sealing substrates 25 are vertically stacked with the vibrating substrate 23 sandwiched therebetween (in FIG. 4, the sealing substrates stacked above are not shown). The sealing substrate 25 has a recess 26 on the surface on the side where the vibration space is formed. Therefore, in the vibrating portion of the piezoelectric member 1, a vibrating space is secured by the concave portions 6 and 8 of the holding members 5 and 7 and the concave portion 26 of the sealing substrate 25.

The external electrode 30 provided at the left end of the piezoelectric component is electrically connected to the lead-out portion 3 a of the vibrating electrode 3 and the capacitive electrodes 11, 14, 17, 20. The external electrode 31 provided at the right end of the piezoelectric component is electrically connected to the lead-out portion 2a of the vibrating electrode 2 and the capacitive electrodes 13, 15, 19, 21. The external electrode 32 provided at the center of the piezoelectric component is electrically connected to the capacitive electrodes 12 and 18. In the capacitance members 10 and 16, between the capacitance electrodes 11 and 12, between the capacitance electrodes 12 and 13, between the capacitance electrodes 12 and 14, between the capacitance electrodes 12 and 15, and between the capacitance electrodes 14 and 15, Capacitors are formed between the quantity electrodes 17 and 18, between the capacity electrodes 18 and 19, between the capacity electrodes 18 and 20, between the capacity electrodes 18 and 21, and between the capacity electrodes 20 and 21. Furthermore, in the sealing substrate 25, capacitance is formed between the external electrodes 30 and 32 and between the external electrodes 31 and 32.

As described above, since the present piezoelectric component has the structure in which the capacitive members 10 and 16 are provided in addition to the holding members 5 and 7, the thickness of the capacitive members 10 and 16 can be made thin, and the surface thereof has unevenness. It can be a flat surface. As a result, the capacitor electrodes 11 to 15 and 17 to 21 can be accurately arranged, have a stable capacitance value, and have a thin built-in capacitor that can be used as an oscillator for an IC card. Molded piezoelectric component is obtained.

The capacitor built-in type piezoelectric component according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the gist thereof. In particular, the capacitive electrode provided on the capacitive member has various shapes.

[0015]

[Effect of the device]

 As is clear from the above description, according to the present invention, since the capacity member is provided separately from the holding member, the thickness of the capacity member can be made thin and the surface thereof can be a flat surface. Therefore, the capacitance electrode provided on the capacitance member forms a large capacitance, and a stable capacitance value without variation can be obtained. As a result, it is possible to obtain a thin capacitor built-in type piezoelectric component which has a stable capacitance value and can be used as an oscillator for an IC card or the like. Further, the capacity formed in the sealing substrate can be added to the capacity formed in the capacity member.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining a manufacturing process of an embodiment of a built-in capacitor type piezoelectric component according to the present invention.

FIG. 2 is a perspective view for explaining a manufacturing process of an embodiment of the built-in capacitor type piezoelectric component according to the present invention.

FIG. 3 is a perspective view showing an external appearance of an embodiment of a piezoelectric component with a built-in capacitor according to the present invention.

FIG. 4 is a horizontal cross-sectional view of the built-in capacitor type piezoelectric component shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piezoelectric member 2,3 ... Vibration electrode 5,7 ... Holding member 10 ... Capacitance member 11, 12, 13, 14, 15 ... Capacitance electrode 16 ... Capacitance member 17, 18, 19, 20, 21 ... Capacitance electrode 23 ... Vibration substrate 25 ... Sealing substrate

Claims (1)

[Scope of utility model registration request] 1. A piezoelectric member having vibrating electrodes on front and back surfaces,
A holding member that holds the piezoelectric member from both sides and a capacitive member that is disposed outside the holding member and that has capacitive electrodes provided on the front and back surfaces constitute one vibrating substrate, and the vibrating substrate is sealed. A built-in capacitor type piezoelectric component, characterized in that it is a laminated structure having a closed vibration space sandwiched by a stop substrate.