JP2012216901A - Complex piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a complex piezoelectric device which improves the productivity.SOLUTION: A complex piezoelectric device includes: a device mounting part 310 including a substrate part 310a having first and second main surfaces and a leg part 310b provided on the second main surface of the substrate part 310a; a first piezoelectric device 100 which includes a first element mounting member 110 having a first recessed space K1 and a first piezoelectric vibration element 120 mounted in the first recessed space K1 and is joined to the first main surface of the substrate part 310a; and a second piezoelectric device 200 which includes a second element mounting member 210 having a second recessed space K2 and a second piezoelectric vibration element 220 mounted in the second recessed space K2 and is joined to the second main surface of the substrate part 310a.

Description

  The present invention relates to a composite piezoelectric device used in electronic equipment and the like.

  As an example, a conventional composite type piezoelectric device mainly includes an element mounting member, a first piezoelectric vibration element, a tuning fork type bending piezoelectric vibration element as a second piezoelectric vibration element, and a lid member. A known structure is known (see, for example, Patent Document 1).

  The element mounting member includes a substrate part, a first frame part, and a second frame part. A first recessed portion space is formed by providing a first frame portion on the main surface of the substrate portion, and a first recessed space is formed by providing a second frame portion on the first frame portion. A pair of second piezoelectric vibration element mounting pads are provided on the first main surface of the first frame exposed in the first recess space. A pair of piezoelectric vibration element mounting pads is provided on the first main surface of the substrate portion exposed in the second recess space. In addition, electrode terminals for external connection are provided at the four corners of the second main surface of the substrate portion. On the piezoelectric vibration element mounting pad, a first piezoelectric vibration element having a pair of excitation electrodes electrically connected via a conductive adhesive on the front and back main surfaces is mounted. The top surface of the first frame portion of the element mounting member surrounding the first piezoelectric vibration element is covered with a metal lid member and joined. Thereby, the first recess space and the second recess space are hermetically sealed. On the second piezoelectric vibration element mounting pad, a tuning fork type bending piezoelectric vibration element which is a second piezoelectric vibration element connected via a conductive adhesive is mounted.

JP 2002-280865 A

  However, in the conventional composite piezoelectric device, the oscillation frequency of any one of the first piezoelectric vibration element mounted on the element mounting member and the tuning fork type bending piezoelectric vibration element which is the second piezoelectric vibration element fluctuates. When the frequency characteristics are bad, both of them need to be discarded, which causes a problem that productivity is lowered.

  This invention is made | formed in view of the said subject, and makes it a subject to provide the composite type piezoelectric device which can improve productivity.

  The composite piezoelectric device of the present invention includes a device mounting member including a substrate portion having first and second main surfaces and a leg portion provided on the second main surface of the substrate portion, and a first recess space. A first piezoelectric device including a first element mounting member having a first piezoelectric vibration element mounted in the first recess space and bonded to the first main surface of the substrate portion; Including a second element mounting member having two recess spaces and a second piezoelectric vibration element mounted in the second recess space, and being bonded to the second main surface of the substrate portion. It is a feature.

  According to the piezoelectric device of the present invention, the device mounting member including the substrate portion and the leg portion, the first piezoelectric device bonded to the first main surface of the substrate portion, and the second main surface of the substrate portion are bonded. By providing the second piezoelectric device, the oscillation frequency of any one of the first piezoelectric vibrating element and the second piezoelectric vibrating element fluctuates, and even if the frequency characteristic is bad, the first Since only one of the piezoelectric device and the second piezoelectric device is discarded, both need not be discarded, and productivity can be improved.

1 is an exploded perspective view showing a composite piezoelectric device according to an embodiment of the present invention. It is AA sectional drawing of FIG. It is a perspective view which shows the element mounting member which comprises the composite type piezoelectric device which concerns on embodiment of this invention. It is a perspective view which shows the tuning fork type bending piezoelectric vibration element which is the 2nd piezoelectric vibration element which comprises the composite type piezoelectric device which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. A case where quartz is used for the piezoelectric vibration element will be described.

  As shown in FIGS. 1 and 2, the composite piezoelectric device 400 according to the embodiment of the present invention includes a first element mounting member 110, a first piezoelectric vibration element 120, and a first lid member 130. The first piezoelectric device 100, the second element mounting member 210, the second piezoelectric vibration element 220, and the second lid member 230, and the device mounting member 310. And is mainly composed. In the composite piezoelectric device 400, the first piezoelectric device 100 is mounted on the first main surface of the device mounting member 310, and the third recessed space formed on the second main surface of the device mounting member 310. A second piezoelectric device 200 is mounted in K3.

(First piezoelectric device)
The first piezoelectric device 100 includes a first element mounting member 110, a first piezoelectric vibration element 120, and a first lid member 130. As shown in FIG. 1 and FIG. 2, the first piezoelectric vibration element 120 is formed by depositing an excitation electrode 122 on a crystal base plate 121, and an alternating voltage from the outside is passed through the excitation electrode 122. When applied to the quartz base plate 121, excitation occurs in a predetermined vibration mode and frequency. The quartz base plate 121 is a substantially flat plate shape that is cut from an artificial crystalline lens at a predetermined cut angle and is subjected to outer shape processing, and has a planar shape of, for example, a quadrangle. The excitation electrode 122 is formed by depositing and forming a metal in a predetermined pattern on both the front and back main surfaces of the crystal base plate 121. The first piezoelectric vibration element 120 as described above is formed on the extraction electrode 124 extending from the excitation electrode 122 and the first bottom surface in the first recess space K1 which are attached to both main surfaces. The piezoelectric vibration element mounting pad 111 is mounted in the first recess space K1 by being electrically and mechanically connected via the conductive adhesive DS. At this time, an end side that is a free end opposite to the side on which the extraction electrode 124 is provided is defined as a distal end portion 123 of the first piezoelectric vibration element 120.

  As shown in FIGS. 1-2, the 1st element mounting member 110 is mainly comprised by the board | substrate part 110a and the frame part 110b. In the first element mounting member 110, a frame portion 110b is provided on the first main surface of the substrate portion 110a to form a first recess space K1.

  In addition, the board | substrate part 110a which comprises this 1st element mounting member 110 is formed by laminating | stacking multiple ceramic materials, such as an alumina ceramic and a glass-ceramic, for example. The frame portion 110b is made of a metal such as 42 alloy or Kovar, and has a frame shape with a punched center.

  The frame portion 110b is connected to the sealing conductor film 113 provided in the peripheral portion by brazing or the like so as to surround the central portion of the first main surface of the substrate portion 110a. A pair of first piezoelectric vibration element mounting pads 111 are provided on the first main surface of the substrate portion 110a exposed in the first recess space K1.

  First element member connection terminals 112 are provided at the four corners of the main surface of the first element mounting member 110 opposite to the surface on which the first piezoelectric vibration element mounting pad 111 is provided. . Two terminals of the first piezoelectric vibration element mounting pad 111 and the first element member connecting terminal 112 are formed on the substrate portion 110a in the first recess space K1 of the first element mounting member 110. A wiring pattern (not shown) having a portion is connected to a via conductor (not shown) formed inside the substrate portion 110a.

  The first lid member 130 is made of, for example, an Fe—Ni alloy (42 alloy), an Fe—Ni—Co alloy (Kovar), or the like. Such a first lid member 130 hermetically seals the first recessed space K1 with nitrogen gas or vacuum. Specifically, the first lid member 130 is placed on the frame portion 110b of the element mounting member 110 in a predetermined atmosphere, and a metal on the surface of the frame portion 110b and a part of the metal of the lid member 130 are welded. As described above, by applying a predetermined current to perform seam welding, the frame portion 110b is joined.

  The conductive adhesive DS contains a conductive powder as a conductive filler in a binder such as a silicone resin. As the conductive powder, aluminum (Al), molybdenum (Mo), tungsten (W) , Platinum (Pt), palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or a combination thereof is used.

  When the first element mounting member 110 is made of alumina ceramic, the first piezoelectric vibration element mounting pad is formed on the surface of the ceramic green sheet obtained by adding and mixing an appropriate organic solvent or the like to a predetermined ceramic material powder. 111, a conductive paste that becomes the element member connecting terminal 112, the sealing conductive film 113, and the like, and a conductive paste that becomes a via conductor in a through-hole previously punched by punching the ceramic green sheet Is manufactured by conventionally known screen printing, and a plurality of these are laminated and press-molded, followed by firing at a high temperature.

(Second piezoelectric device)
The second piezoelectric device 100 includes a second element mounting member 210, a second piezoelectric vibration element 220, and a second lid member 230. The second piezoelectric vibration element 220 will be described as a tuning fork type bending piezoelectric vibration element 220. As shown in FIG. 4, the tuning fork-type bending piezoelectric vibration element 220 includes a crystal piece, excitation electrodes 223a, 223b, 224a and 224b provided on the surface of the crystal piece, connection electrodes 225a and 225b, frequency The adjustment metal films 226a and 226b are roughly configured.

  As shown in FIG. 4, the crystal piece is made of, for example, crystal, and includes a base portion 221 having a flat plate shape and a pair of vibrating arm portions 222 extending in the same direction from one side of the base portion 221.

  As shown in FIG. 4, the excitation electrode 223a is provided on the front and back main surfaces of the first vibrating arm portion 222a. The excitation electrode 223b is provided on both opposing side surfaces of the first vibrating arm portion 222a. The frequency-adjusting metal film 226a is provided on the front main surface and the front end portions of both side surfaces of the first vibrating arm portion 222a. The connection electrode 225 a is provided on the front and back main surfaces of the base 221 on the first vibrating arm 222 a side of the base 221.

  The excitation electrode 224a is provided on the front and back main surfaces of the second vibrating arm portion 222b. The excitation electrode 224b is provided on both opposite side surfaces of the second vibrating arm portion 222b. The frequency adjusting metal film 226b is provided on the front main surface and the tip of the side surface of the second vibrating arm portion 222b. The connection electrode 225 b is provided on the front and back main surfaces of the base portion 221 on the second vibrating arm portion 222 b side of the base portion 221.

  The tuning fork type bending piezoelectric vibration element 220 can adjust the vibration frequency value to a desired value by increasing or decreasing the amount of the metal constituting the frequency adjusting metal films 226a and 226b.

  As shown in FIG. 4, the excitation electrodes 224a and 224b, the frequency adjusting metal film 226b, and the connection electrode 225b are electrically connected by, for example, a conductive wiring pattern provided on the surface of the crystal piece. . The connection electrode 225b is electrically connected to the excitation electrode 223a through a conductive wiring pattern provided on the base 221. The connection electrode 225b is electrically connected to the excitation electrode 224b.

  The excitation electrodes 223b and 224a, the frequency adjusting metal film 226a, and the connection electrode 225a are electrically connected by, for example, a conductive wiring pattern provided on the surface of the crystal piece. The connection electrode 225a is electrically connected to the excitation electrode 223b and the frequency adjusting metal film 226a. In addition, the conductive wiring pattern provided on the front main surface of the base 221 is electrically connected to the excitation electrode 223a and the excitation electrode 224b.

  Each excitation electrode, connection electrode, frequency adjusting metal film, and conductive wiring pattern are composed of a Cr layer as a base metal and an Au layer provided on the base metal.

  When this tuning fork type bending piezoelectric vibrating element 220 is vibrated, an alternating voltage is applied to the connection electrodes 225a and 225b. When an electrical state after application is instantaneously captured, the excitation electrode 223b of the first vibrating arm 222b becomes a + (plus) potential, the excitation electrode 223a becomes a-(minus) potential, and changes from + to-. An electric field is generated. On the other hand, the excitation electrode of the second vibrating arm portion 222b at this time has a polarity opposite to the polarity generated in the exciting electrode of the first vibrating arm portion 222a. These applied electric fields cause an expansion / contraction phenomenon in the first vibrating arm portion 222a and the second vibrating arm portion 222b, and a bending vibration having a resonance frequency set in each vibrating arm portion 222 is obtained.

  As shown in FIGS. 1-2, the 2nd element mounting member 210 is mainly comprised by the board | substrate part 210a and the frame part 210b. In the second element mounting member 210, a frame portion 210b is provided on the first main surface of the substrate portion 210a, and a second recessed space K2 is formed.

  In addition, the board | substrate part 210a and the frame part 210b which comprise this 2nd element mounting member 210 are formed by laminating | stacking multiple ceramic materials, such as an alumina ceramic and glass-ceramics, for example. A pair of second piezoelectric vibration element mounting pads 211 are provided on the first main surface of the substrate portion 210a exposed in the second recess space K2.

  A second element member connection terminal 212 is provided on the main surface of the second element mounting member 210 opposite to the surface on which the second piezoelectric vibration element mounting pad 211 is provided. The second piezoelectric vibration element mounting pad 211 and the element member connection terminal 212 have a wiring pattern (not shown) having a portion formed on the substrate portion 210a in the second recessed space K2 of the second element mounting member 210. Connected).

  The second lid member 230 is made of, for example, an Fe—Ni alloy (42 alloy), an Fe—Ni—Co alloy (Kovar), or the like. Such a second lid member 230 hermetically seals the second recessed space K2 with nitrogen gas or vacuum. Specifically, the second lid member 230 is placed on the frame part 210b of the second element mounting member 210 in a predetermined atmosphere, and the sealing conductor pattern (not shown) of the frame part 210b is connected to the second lid member 230. The sealing member (not shown) of the second lid member 230 is welded to the frame portion 210b by applying a predetermined current so as to be welded.

  The conductive adhesive DS contains a conductive powder as a conductive filler in a binder such as a silicone resin. As the conductive powder, aluminum (Al), molybdenum (Mo), tungsten (W ), Platinum (Pt), palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or a combination thereof is used. .

(Device mounting material)
As shown in FIGS. 1-3, the device mounting member 310 is mainly comprised by the board | substrate part 310a and the leg part 310b. The leg portion 310b is, for example, a frame member, a pair of wall members, or a plurality of pillar members. In the device mounting member 310, a leg portion 310b is provided on the second main surface of the substrate portion 310a to form a third recess space K2.

  In addition, the board | substrate part 310a and the leg part 310b which comprise this device mounting member 310 are formed by laminating | stacking multiple ceramic materials, such as an alumina ceramic and glass-ceramics, for example.

  A first piezoelectric device mounting pad 311 is provided on the first main surface of the substrate portion 310a. Further, as shown in FIG. 3, a second piezoelectric device mounting pad 312 is provided on the second main surface of the substrate portion 310a exposed in the third recess space K3. Further, as shown in FIG. 3, an external connection electrode terminal G is provided on the second main surface of the leg portion 310b. Further, one of the external connection electrode terminals G may be a ground terminal.

  The first piezoelectric device mounting pad 311 and the second piezoelectric device mounting pad 312 are formed by a wiring pattern (not shown) having a portion formed on the substrate portion 310a of the device mounting member 310 and a via conductor (not shown). The external connection electrode terminal G is connected.

  As shown in FIG. 2, the first piezoelectric device mounting pad 311 is electrically bonded to the first element member connection terminal 112 of the first piezoelectric device 100 via a conductive bonding material DH. . For example, the conductive bonding material DH contains conductive powder as a conductive filler in a binder such as solder or silicone resin.

  As shown in FIG. 2, the second piezoelectric device mounting pad 312 is electrically bonded to the second element member connection terminal 212 of the second piezoelectric device 200 via the conductive bonding material DH. ing. That is, the second piezoelectric device 200 is bonded to the second piezoelectric device mounting pad 312 so as to be accommodated in the third recessed space K3.

  In this way, the first element member connection terminal 112 of the first piezoelectric device 100 and the second element member connection terminal 212 of the second piezoelectric device 200 are connected to the third element mounting member 310. It is electrically connected to an external connection electrode terminal G provided on the second main surface of the leg 310b.

  According to the composite piezoelectric device 400 of the present invention, the device mounting member 300 including the substrate portion 310a and the leg portion 310b, the first piezoelectric device 100 bonded to the first main surface of the substrate portion 310a, and the substrate portion. By including the second piezoelectric device 200 joined to the second main surface of 310a, the oscillation frequency of any one of the first piezoelectric vibration element 120 and the second piezoelectric vibration element 220 varies. Even when the frequency characteristics are poor, since only one of the first piezoelectric device 100 and the second piezoelectric device 200 is discarded, both do not need to be discarded, and the productivity can be improved.

  In addition, this invention is not limited to the said embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, in the above-described embodiment, the case where crystal is used as the piezoelectric material constituting the piezoelectric vibration element 120 has been described. However, as other piezoelectric materials, lithium niobate, lithium tantalate, or piezoelectric ceramics is used as the piezoelectric material. The piezoelectric vibration element used may be used.

  In the structure shown in FIGS. 1 and 2, the piezoelectric device having the flat plate type piezoelectric vibration element 120 is provided on the upper side of the substrate portion 310a, and the piezoelectric device having the tuning fork type bending piezoelectric vibration element 220 is the substrate. On the contrary, a piezoelectric device having a tuning fork type bending piezoelectric vibration element 220 is provided on the upper side of the substrate part 310a and has a flat plate type piezoelectric vibration element 120. The structure provided below the board | substrate part 310a may be sufficient. In general, the piezoelectric device 200 having the tuning fork-type bending piezoelectric vibration element 220 can be made smaller than the piezoelectric device having the flat plate-type piezoelectric vibration element 120, and is shown in FIGS. 1 and 2. As described above, a structure in which the piezoelectric device having the tuning fork type bending piezoelectric vibration element 220 is provided below the substrate portion 310 a and is provided in the leg portion 310 b of the device mounting member 310 is preferable.

  The first piezoelectric vibration element 120 has been described as a plate-type piezoelectric vibration element and the second piezoelectric vibration element 220 has been described as a tuning-fork type bending piezoelectric vibration element. Other piezoelectric vibration elements such as a surface acoustic wave (SAW) element may be used.

DESCRIPTION OF SYMBOLS 110 ... 1st element mounting member 210 ... 2nd element mounting member 310 ... Device mounting member 110a, 210a, 310a ... Board | substrate part 110b, 210b ... Frame part 310b ... Leg Part 111... First piezoelectric vibration element mounting pad 211... Second piezoelectric vibration element mounting pad 112... First element member connection terminal 212. ... 1st piezoelectric device mounting pad 312 ... 2nd piezoelectric device mounting pad 120 ... 1st piezoelectric vibration element 220 ... 2nd piezoelectric vibration element (tuning fork type bending piezoelectric vibration element)
DESCRIPTION OF SYMBOLS 130 ... 1st cover member 230 ... 2nd cover member 100 ... 1st piezoelectric device 200 ... 2nd piezoelectric device 300 ... Device mounting member 400 ... Composite type piezoelectricity Device K1 ... 1st recessed space K2 ... 2nd recessed space K3 ... 3rd recessed space DS ... Conductive adhesive DH ... Conductive bonding material HB ... Sealing Conductor film G ... Electrode terminal for external connection

Claims (1)

A device mounting member including a substrate portion having first and second main surfaces; and a leg portion provided on the second main surface of the substrate portion;
A first element mounting member having a first recess space and a first piezoelectric vibration element mounted in the first recess space are bonded to the first main surface of the substrate portion. A first piezoelectric device formed;
A second element mounting member having a second recess space; and a second piezoelectric vibration element mounted in the second recess space, and bonded to the second main surface of the substrate portion. And a second piezoelectric device. The composite piezoelectric device comprising:

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