JP2017135524A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device which inhibits a joint material from adhering to a piezoelectric vibration element and has a stable vibration frequency and a good CI value.SOLUTION: A piezoelectric vibrator 100 includes: an element mounting member 110 including a substrate 111 having a rectangular shape in a plan view and a frame body 112 provided on an upper surface of the substrate 111; a piezoelectric vibration element 120 mounted in a recessed part 113 formed by the substrate 111 and the frame body 112; and a flat-plate like lid member 140 which is joined to an upper surface of the frame body 112 by a joint material 150 to hermetically seal a space in the recessed part 113 and has a rectangular shape in the plan view. The lid member 140 includes a groove part 141 which is provided along an edge part of a portion of a lower surface of the lid member 140, which is exposed to the recessed part 113 when the lid member 140 is joined to the upper surface of the frame body 112.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a piezoelectric device used in electronic equipment.

  Piezoelectric devices such as piezoelectric vibrators and piezoelectric oscillators that have a piezoelectric resonator inside are used as one of electronic components, as a reference signal source or clock signal source, inside an electronic device such as a computer, mobile phone, or small information device. Installed and used.

  For example, a conventional piezoelectric vibrator has a conductive property in which a piezoelectric vibration element provided with an excitation electrode and a connection electrode is applied to an element mounting member provided with a pair of electrode pads on the upper surface of each electrode pad. By bonding and fixing the connection electrode to the adhesive, the piezoelectric vibration element is mounted on the element mounting member, and the lid member having a flat upper and lower main surface is bonded to the element mounting member to hermetically seal the piezoelectric vibration element. (For example, refer to Patent Document 1 or 2).

JP2015-154371A Japanese Patent Laying-Open No. 2015-207854

  In conventional piezoelectric devices, generally, the piezoelectric element mounted in the recess of the element mounting member is formed by bonding the upper surface of the frame constituting the element mounting member and the lower surface of the lid member with a thermoplastic bonding material. The vibration element was hermetically sealed. However, as miniaturization of the piezoelectric device progresses, the position of the piezoelectric vibration element mounted in the recess of the element mounting member and the joint portion between the lid member and the element mounting member become very close. In such a form, when the lid member and the element mounting member are bonded by the bonding material, the bonding material whose fluidity is increased by heating flows out from the bonding portion into the recess, and the discharged bonding material becomes the piezoelectric vibration element. May adhere. When the bonding material adheres to the piezoelectric vibration element as described above, the vibration of the piezoelectric vibration element may be hindered, and the vibration frequency may become unstable or the crystal impedance (hereinafter referred to as CI) value may deteriorate. It was.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a piezoelectric device that suppresses adhesion of a bonding material to a piezoelectric vibration element, has a stable vibration frequency, and has a good CI value.

  The piezoelectric device of the present invention is a piezoelectric device mounted in a recess formed by an element mounting member including a rectangular substrate in plan view and a frame provided on the upper surface of the substrate, and the substrate and the frame. The vibration element and a lid member having a flat plate shape with a rectangular shape in plan view that hermetically seals the space in the recess by joining the upper surface of the frame body with a joining material. It comprises a groove provided along the edge of the portion exposed to the recess in the lower surface of the lid member when bonded to the upper surface of the body.

  The piezoelectric device of the present invention is a piezoelectric device mounted in a recess formed by an element mounting member including a rectangular substrate in plan view and a frame provided on the upper surface of the substrate, and the substrate and the frame. And a lid member having a rectangular shape in plan view and hermetically sealing the space in the recess by joining the upper surface of the frame body with a joining material, and the lid member includes a lid member. A groove provided along the edge of the portion exposed to the recess in the lower surface of the lid member when joined to the upper surface of the frame is provided.

  With such a configuration, even if the bonding material whose fluidity has been increased by heating flows out from the bonding portion into the recess, the flowing out bonding material flows into the groove and solidifies so that the bonding material is stored in the groove. can do. Therefore, the piezoelectric device can suppress the bonding material that has flowed into the recess from adhering to the piezoelectric vibration element, and can reduce the inhibition of vibration. In addition, such a piezoelectric device can stably obtain vibration of a desired frequency, and can have a good CI value.

1 is an exploded perspective view showing a piezoelectric device according to an embodiment of the present invention. 1A and 1B show a piezoelectric device according to an embodiment of the present invention, in which FIG. 1A is a cross-sectional view taken along the line A-A in FIG. 1, and FIG. FIG. It is sectional drawing when it cut | disconnects in the same position as Fig.2 (a) about the 1st modification of the piezoelectric device which concerns on embodiment of this invention. It is shown about the 2nd modification of the piezoelectric device which concerns on embodiment of this invention, (a) is sectional drawing when cut | disconnecting in the same position as Fig.2 (a), (b) is (a). It is the expanded sectional view which expanded and showed only the cover member the virtual circle B part shown in FIG. It is shown about the 3rd modification of the piezoelectric device which concerns on embodiment of this invention, (a) is sectional drawing when cut | disconnecting in the same position as Fig.2 (a), (b) is (a). It is the expanded sectional view which expanded and showed only the cover member the virtual circle C part shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing a piezoelectric device according to an embodiment of the present invention. 2A and 2B show a piezoelectric device according to an embodiment of the present invention, in which FIG. 2A is a cross-sectional view taken along the line A-A in FIG. 1 and FIG. It is the top view seen from the element side. FIG. 3 is a cross-sectional view of the first modification of the piezoelectric device according to the embodiment of the present invention when cut at the same position as in FIG. FIG. 4 shows a second modification of the piezoelectric device according to the embodiment of the present invention, wherein (a) is a cross-sectional view taken at the same position as FIG. 2 (a), and (b). FIG. 4 is an enlarged cross-sectional view showing only the lid member of the virtual circle B portion shown in FIG. FIG. 5 shows a third modification of the piezoelectric device according to the embodiment of the present invention, wherein (a) is a cross-sectional view taken at the same position as FIG. 2 (a), and (b). FIG. 4 is an enlarged cross-sectional view showing only a lid member in an imaginary circle C portion shown in FIG.

  In each drawing, for clarity of explanation, a part of the structure is not shown, and some dimensions are exaggerated. Further, in order to simplify the description in each drawing, except for FIG. 2B, the upper part of the sheet on which the drawing is described is described as the upper part of each piezoelectric device and each component constituting the piezoelectric device. As for FIG. 2B, the illustrated surface is described as the lower surface, and the opposite surface is described as the upper surface.

  As an embodiment of the present invention, a piezoelectric vibrator that is one of piezoelectric devices will be described. As shown in FIGS. 1 and 2, the piezoelectric vibrator 100 mainly includes an element mounting member 110, a piezoelectric vibration element 120, a conductive adhesive 130, a lid member 140, and a bonding material 150. Yes. The piezoelectric vibrator 100 is used for generating and outputting a reference signal used in an electronic device or the like.

  The element mounting member 110 is for stably mounting a piezoelectric vibration element 120 described later. The element mounting member 110 is mainly composed of a substrate 111, a frame body 112, an electrode pad 114, and an external connection electrode pad 115.

  The substrate 111 is a flat plate having a rectangular shape in plan view, and functions as a mounting member for mounting the piezoelectric vibration element 120 on the upper surface thereof. An electrode pad 114 for inputting / outputting signals to / from the piezoelectric vibration element 120 is provided on the upper surface of the substrate 111, and the piezoelectric vibrator 100 is mounted on the lower surface while inputting / outputting signals to / from an external mounting substrate. External connection electrode pads 115 are provided for fixing to the substrate. A wiring pattern (not shown) for electrically connecting the electrode pad 114 and the external connection electrode pad 115 is provided on the surface and inside of the substrate 111. The substrate 111 is made of, for example, a ceramic material such as alumina ceramic or glass-ceramic, or an insulating material that is glass-epoxy.

  The frame body 112 is provided along the outer peripheral edge of the upper surface of the substrate 111, and is for forming the recess 113 on the upper surface side of the substrate 111. The frame body 112 is made of, for example, a ceramic material such as alumina ceramic or glass-ceramic, or an insulating material that is glass-epoxy. The size of the inner periphery of the frame body 112, that is, the size of the opening of the recess 113 is such that a piezoelectric vibration element 120 described later can be mounted in the recess 113 in the lateral direction.

  The electrode pad 114 is electrically connected using a piezoelectric vibration element 120 described later and a conductive adhesive 130, and inputs / outputs signals to / from the piezoelectric vibration element 120. A pair of electrode pads 114 are arranged along one short side of the upper surface of the substrate 111 exposed in the recess 113, and the piezoelectric vibration element 120 is disposed at a predetermined position in the recess 113. It is provided at a position facing the connection electrode 123 provided at 120. The electrode pad 114 is electrically connected to a predetermined external connection electrode pad 115 by a wiring pattern (not shown) provided in the substrate 111. The electrode pad 114 is formed by metallizing a conductive metal such as gold.

  The external connection electrode pad 115 functions as an electrode pad for electrical connection via a conductive bonding material such as solder when the piezoelectric vibrator 100 is mounted on an external mounting substrate. A total of four external connection electrode pads 115 are provided at each of the four corners of the lower surface of the substrate 111. Each of the external connection electrode pads 115 includes, for example, a piezoelectric vibration element input terminal, a piezoelectric vibration element output terminal, and a ground. It is comprised by the terminal or the non-connect terminal. Of the external connection electrode pads 115, those serving as piezoelectric vibration element input terminals and piezoelectric vibration element output terminals are electrically connected to the electrode pads 114, and those serving as ground terminals are electrically connected to a lid member 130 described later. Connected to.

  The piezoelectric vibration element 120 generates an electric signal having a desired frequency using, for example, thickness shear vibration. As shown in FIG. 1, the piezoelectric vibration element 120 mainly includes a piezoelectric element 121, an excitation electrode 122 that excites thickness shear vibration provided on the upper surface of the piezoelectric element 121, and a connection electrode 123. .

  The piezoelectric element 121 is a flat plate having a rectangular shape in plan view, and a thin crystal plate that is cut from the artificial crystalline lens at a predetermined angle and is subjected to external processing is used. In this embodiment, a quartz thin plate is used for the piezoelectric element 121. However, a thin plate made of a single crystal material having piezoelectricity such as lithium tantalate or lithium niobate may be used.

  The excitation electrode 122 is for generating a thickness shear vibration in the piezoelectric element 121. One excitation electrode 122 is provided at the center of the upper surface and the lower surface of the piezoelectric element 121, and is opposed to the piezoelectric element 121. The excitation electrodes 122 have, for example, the same shape and size as each other, and overlap in plan perspective. The shape of the excitation electrode 122 is, for example, a substantially rectangular shape having four sides parallel to the four sides of the main surface of the piezoelectric element 121. The excitation electrode 122 is formed by laminating a conductive metal such as gold, aluminum, nickel, chromium, titanium, or an alloy containing these metals on the upper and lower surfaces of the piezoelectric element 121 by vapor deposition or sputtering. In addition, it is formed by a manufacturing method such as a photolithography method. For example, the excitation electrode 122 may have a three-layer structure of Au, Ni, and Cr in order from the upper surface.

  The connection electrode 123 is for inputting and outputting signals between the electrode pad 114 provided on the element mounting member 110 and the excitation electrode 122 of the piezoelectric vibration element 120. As shown in FIGS. 1 and 2, the connection electrode 123 is provided at each terminal portion of the wiring pattern drawn out from each excitation electrode 122, and from the upper surface of both corners of one short side of the piezoelectric element 121. A total of two are formed from the side surface to the lower surface. The connection electrode 123 is electrically connected to an electrode pad 114 provided on the element mounting member 110 by a conductive adhesive 130. The connection electrode 123 is formed by depositing or depositing conductive metal such as gold, aluminum, nickel, chromium, titanium, or an alloy containing these metals on the upper and lower side surfaces of both corners of one short side of the piezoelectric element 121. After being formed into a thin film by sputtering or the like, it is formed by a manufacturing method such as a photolithography method. For example, the connection electrode 123 may have a three-layer structure of metals of Au, Ni, and Cr in order from the top surface.

  The conductive adhesive 130 is for fixing the piezoelectric vibration element 120 to the electrode pad 114 while electrically connecting the connection electrode 123 and the electrode pad 114. The conductive adhesive 130 is made of an epoxy-based or silicone-based synthetic resin containing silver or the like as a conductive filler, and has a viscosity of 20 to 40 Pa · s. For example, an appropriate amount of the conductive adhesive 130 is applied to the upper surface of the electrode pad 114 in a fluid state, and the piezoelectric vibration element 120 is disposed so that the conductive adhesive 130 and the connection electrode 123 are in contact with each other. Subsequently, the conductive adhesive 130 is solidified by heating at 120 to 200 ° C., thereby fixing the piezoelectric vibrating element 120 to the electrode pad 114 while electrically connecting the connection electrode 123 and the electrode pad 114.

  The lid member 140 is for hermetically sealing the recess 113 in a vacuum state or the recess 113 filled with an inert gas such as nitrogen, argon, or helium. The lid member 140 has a flat plate shape that is rectangular in plan view, and has a size that covers and closes the opening of the recess 113. The lid member 140 is disposed on the opening side main surface of the frame body 112 so as to cover and close the opening portion of the recess 113, and is bonded to the opening side upper surface of the frame body 112 via the bonding material 150. The lid member 140 is made of, for example, an alloy or ceramic containing at least one of iron, nickel, and cobalt, and has a thickness dimension of, for example, 0.2 to 1.0 mm.

  A groove 141 is provided on the lower surface of the lid member 140 exposed at the recess 113. The groove portion 141 is used for accumulating the bonding material 150 that has flowed out from the bonding portion to the concave portion 113 side when the lid member 140 and the opening-side upper surface of the frame body 112 are bonded by the bonding material 150. The groove portion 141 has a shape that opens on the lower surface side of the lid member 140 and is recessed in the upper surface direction of the lid member 140, and is along the four side edge portions of the lower surface of the lid member 140 that is exposed to the recess 113. It is provided in one annular shape, and is formed such that the width and depth of the groove 141 are in the range of 1 to 50% of the thickness of the lid member. The shape of the groove portion 141 is not limited to an annular shape, and a total of four groove portions may be provided one by one along the four edge portions of the lower surface of the lid member 140 exposed at the recess 113.

  The bonding material 150 is used to bond the element mounting member 110 and the lid member 140 so that the inside of the recess 113 is airtight. The bonding material 150 is made of, for example, low-melting glass, and is provided on the entire upper surface of the element mounting member 110 on the opening side of the recess 113 of the frame body 112. As an example of a method of joining the lid member 140 and the element mounting member 120 in the present invention, the ceramic lid member 140 is disposed so that the upper surface thereof faces the direction of gravity, and the piezoelectric vibration element 120 is mounted in the recess 113. The element mounting member 120 is disposed at a predetermined position on the lower surface of the lid member 140 such that the bonding material 150 provided on the upper surface on the opening side of the recess 113 of the frame 112 of the element mounting member 120 is in contact with the predetermined temperature. By heating, the bonding material 150 is melted, and then the bonding material 140 is cooled and solidified, whereby the lid member 140 and the element mounting member 120 are bonded via the bonding material 150 and the inside of the recess 113 is hermetically sealed. At this time, the bonding material 150 that has melted and flowed into the recess 113 flows into the groove 141 due to the action of gravity. The bonding material 150 that has flowed into the groove 141 is stored in the groove 141 by being cooled and solidified in the groove 141. As another example, in the case of the metal lid member 140, the element mounting member 120 in which the piezoelectric vibration element 120 is mounted in the recess 113 is arranged so that the opening side of the recess 113 faces upward, and the lid member 140 is arranged. Is disposed on the upper surface of the frame body 112 provided with the bonding material 150 with the lower surface provided with the groove portion 141 facing the element mounting member 120 side, and heated at a predetermined temperature to melt the bonding material 150. By cooling and solidifying the bonding material 140, the lid member 140 and the element mounting member 120 are bonded via the bonding material 150, and the inside of the recess 113 is hermetically sealed. At that time, the bonding material 150 that has melted and flowed into the concave portion 113 crawls up regardless of the influence of gravity due to the wettability with the lid member 140 in the surface tension, and flows into the groove 141. The bonding material 150 that has flowed into the groove 141 is stored in the groove 141 by being cooled and solidified in the groove 141.

  A piezoelectric vibrator 100 that is a piezoelectric device according to an embodiment of the present invention includes an element mounting member 110 including a substrate 111 having a rectangular shape in plan view, and a frame body 112 provided on the upper surface of the substrate 111, and a substrate 111. The piezoelectric vibration element 120 mounted in the recess 113 formed by the frame 112 and the rectangular shape in plan view that hermetically seals the space in the recess 113 by bonding the upper surface of the frame 112 with the bonding material 150. And a flat lid member 140. The lid member 140 has a marginal portion of a portion of the lower surface of the lid member 140 exposed to the recess 113 when the lid member 140 is joined to the upper surface of the frame body 112. The groove part 141 provided along is provided.

  With such a configuration, even if the bonding material 150 whose fluidity has been increased by heating flows out from the bonding portion into the recess 113, the bonding material 150 that has flowed out flows into the groove 141 and is solidified. Can be stored in the groove 141. Therefore, the piezoelectric device 100 can suppress the bonding material 150 that has flowed into the recess 113 from adhering to the piezoelectric vibration element 120, and can reduce the inhibition of vibration. In addition, such a piezoelectric device 100 can stably obtain vibration of a desired frequency, and can have a good CI value. Further, when the bonding material 150 flows into the groove 141 and solidifies, the bonding area between the bonding material 150 and the lid member 140 increases. Therefore, the bonding strength between the bonding material 150 and the lid member 140 is improved, and the piezoelectric device 100 having high impact resistance can be obtained.

  Further, the groove portion 141 is provided in an annular shape along the four edge portions of the portion of the lower surface of the lid member 140 exposed at the recess 113. By adopting such a configuration, the groove portion 141 is compared with the case where a total of four groove portions are formed one by one along the four edge portions of the portion exposed to the recess 113 in the lower surface of the lid member 140. It becomes possible to store the bonding material 150 that has flowed out to the concave portion 113 side from the bonding portion in the groove portion 141 without leakage, and can further prevent the bonding material 150 that has flowed into the concave portion 113 from adhering to the piezoelectric vibration element 120. Further, it is possible to further reduce the inhibition of vibration.

(First modification)
A first modification of the piezoelectric device according to the embodiment will be described below. In the first modified example, the same components as those of the piezoelectric vibrator 100 which is the piezoelectric device of the embodiment are denoted by the same reference numerals as those assigned to the respective components of the piezoelectric vibrator 100, and the description thereof will be given. Omitted. As shown in FIG. 3, the piezoelectric vibrator 200 according to the first modified example is different from the piezoelectric vibrator 100 of the embodiment in the form of the groove portion 241.

  As shown in FIG. 3, the piezoelectric vibrator 200 that is a piezoelectric device mainly includes an element mounting member 110, a piezoelectric vibration element 120, a conductive adhesive 130, a lid member 240, and a bonding material 150. Yes.

  The lid member 240 is for hermetically sealing the concave portion 113 in a vacuum state or the concave portion 113 filled with an inert gas such as nitrogen, argon, or helium. The lid member 240 has a rectangular plate shape in plan view, and has a size that covers and closes the opening of the recess 113. The lid member 240 is disposed on the opening side main surface of the frame 112 so as to cover and close the opening of the recess 113, and is bonded to the opening side upper surface of the frame 112 via the bonding material 150. The lid member 240 is made of, for example, an alloy or ceramic containing at least one of iron, nickel, and cobalt, and has a thickness dimension of, for example, 0.2 to 1.0 mm.

  A groove 241 is provided on the lower surface of the lid member 240 exposed in the recess 113 in the first modification. The groove portion 241 is used to collect the bonding material 150 that has flowed out from the bonding location to the concave portion 113 side when the lid member 240 and the opening-side upper surface of the frame body 112 are bonded by the bonding material 150. The groove portion 241 has a shape that opens to the lower surface side of the lid member 240 and is recessed in the upper surface direction of the lid member 240, and the side surface on the outer side of the groove portion 241 and the side surface on the concave portion 113 side of the frame portion 112 are flush. The groove portion 241 is formed so that the width and depth of the groove portion 241 are in the range of 1 to 50% of the thickness of the lid member 240. The shape of the groove portion 241 is not limited to an annular shape, and a total of four groove portions may be provided, one for each of the four edge portions of the lower surface of the lid member 241 exposed at the recess 113.

  In the piezoelectric vibrator 200 according to the first modification, the groove portion 241 is provided at a position where the outer side surface of the groove portion 241 and the side surface on the concave portion 113 side of the frame portion 112 are on the same plane. With such a configuration, the side surface on the concave portion 113 side of the frame portion 112 and the outer side surface of the groove portion 241 are smooth without a step, so that the bonding material 150 whose fluidity is increased by heating enters the concave portion 113 from the joint portion. Even if it flows out, it is possible to make it easier for the bonding material 150 that has flowed out to flow into the groove portion 241 as compared with the case of the piezoelectric vibrator 100 having a step. Therefore, the piezoelectric device 200 can further reduce the bonding material 150 exposed in the recess 113, and can further suppress adhesion to the piezoelectric vibration element 120, further reducing the inhibition of vibration. be able to. In addition, such a piezoelectric device 200 can stably obtain vibration of a desired frequency, and can have a good CI value.

(Second modification)
A second modification of the piezoelectric device according to the embodiment will be described below. In the second modification, the same components as those of the piezoelectric vibrator 100 which is the piezoelectric device according to the embodiment are denoted by the same reference numerals as those assigned to the respective components of the piezoelectric vibrator 100, and the description thereof will be given. Omitted. As shown in FIG. 4, a piezoelectric vibrator 300 according to the second modified example is different from the piezoelectric vibrator 100 of the embodiment in the form of the groove portion 341.

  As shown in FIG. 4, the piezoelectric vibrator 300 that is a piezoelectric device mainly includes an element mounting member 110, a piezoelectric vibration element 120, a conductive adhesive 130, a lid member 340, and a bonding material 150. Yes.

  The lid member 340 hermetically seals the recess 113 in a vacuum state or the recess 113 filled with an inert gas such as nitrogen, argon, or helium. The lid member 340 has a flat plate shape that is rectangular in plan view, and has a size that covers and closes the opening of the recess 113. The lid member 340 is disposed on the opening-side main surface of the frame body 112 so as to cover and close the opening of the recess 113, and is bonded to the opening-side upper surface of the frame body 112 via the bonding material 150. The lid member 340 is made of, for example, an alloy or ceramic containing at least one of iron, nickel, and cobalt, and has a thickness dimension of, for example, 0.2 to 1.0 mm.

  A groove portion 341 is provided on the lower surface of the lid member 340 exposed in the concave portion 113 in the first modification. The groove portion 341 is used to store the bonding material 150 that has flowed out from the bonding portion to the recess 113 side when the lid member 340 and the upper surface on the opening side of the frame body 112 are bonded by the bonding material 150. The groove portion 341 has a shape that opens in the lower surface direction of the lid member 340 and is recessed in the upper surface direction of the lid member 340, and along the four edge portions of the lower surface of the lid member 340 that is exposed to the recess 113. It is provided in one annular shape, and is formed such that the width and depth of the groove 341 are in the range of 1 to 50% of the thickness of the lid member. The shape of the groove portion 341 is not limited to an annular shape, and a total of four groove portions may be provided one by one along the four edge portions of the lower surface of the lid member 340 exposed at the recess 113.

  Further, the groove portion 341 includes a first protrusion 342 provided so as to protrude from the edge portion of the opening portion on the inner side surface of the groove portion 341 toward the edge portion of the opening portion on the outer side surface of the groove portion 341. . The first protrusion 342 is used to prevent the bonding material 150 housed in the groove 341 from entering the recess 113. The first projecting portion 342 is provided on the entire groove portion 341, and the projecting dimension of the first projecting portion 342 is formed in a range of 50 to 80% of the width of the groove portion 341. The first protrusion 342 is formed integrally with the lid member 340.

  The piezoelectric vibrator 300 according to the second modified example is provided with a first protrusion provided so as to protrude from the edge of the opening on the inner side surface of the groove 341 toward the edge of the opening on the outer side surface of the groove 341. 342 is provided. With such a configuration, even if the bonding material 150 accommodated in the groove portion 341 is separated from the groove portion 341 due to an external impact or the like, it is the first that the separated bonding material 150 comes out of the groove portion 341. It can be suppressed by the protrusion 342. Therefore, it is possible to prevent the bonding material 150 separated from the inside of the groove portion 341 from entering the concave portion 113 and adhering to the piezoelectric vibration element 120, and the vibration can be further reduced. Further, such a piezoelectric device 300 can stably obtain vibration of a desired frequency, and can have a good CI value.

(Third modification)
A third modification of the piezoelectric device according to the embodiment will be described below. In the third modified example, the same components as those of the piezoelectric vibrator 100 which is the piezoelectric device of the embodiment are denoted by the same reference numerals as those assigned to the respective components of the piezoelectric vibrator 100, and the description thereof will be given. Omitted. As shown in FIG. 5, a piezoelectric vibrator 400 as a third modified example is different from the piezoelectric vibrator 100 of the embodiment in the form of the groove portion 441.

  As shown in FIG. 5, the piezoelectric vibrator 400 that is a piezoelectric device mainly includes an element mounting member 110, a piezoelectric vibration element 120, a conductive adhesive 130, a lid member 440, and a bonding material 150. Yes.

  The lid member 440 hermetically seals the recess 113 in a vacuum state or the recess 113 filled with an inert gas such as nitrogen, argon, or helium. The lid member 440 has a rectangular plate shape in plan view, and has a size that covers and closes the opening of the recess 113. The lid member 440 is arranged on the opening side main surface of the frame body 112 so as to cover and close the opening portion of the recess 113, and is bonded to the opening side upper surface of the frame body 112 via the bonding material 150. The lid member 440 is made of, for example, an alloy or ceramic containing at least one of iron, nickel, and cobalt, and has a thickness dimension of, for example, 0.2 to 1.0 mm.

  A groove portion 441 is provided on the lower surface of the lid member 440 exposed in the recess 113 in the third modification. The groove portion 441 is used to store the bonding material 150 that has flowed out from the bonding portion to the concave portion 113 side when the lid member 440 and the opening-side upper surface of the frame body 112 are bonded by the bonding material 150. The groove portion 441 has a shape that opens in the lower surface direction of the lid member 440 and is recessed in the upper surface direction of the lid member 440, and is along the four edge portions of the lower surface of the lid member 440 that is exposed in the recess 113. It is provided in one annular shape, and is formed such that the width and depth of the groove portion 441 are in the range of 1 to 50% of the thickness of the lid member. The shape of the groove portion 441 is not limited to an annular shape, and a total of four groove portions may be provided one by one along the four edge portions of the lower surface of the lid member 440 exposed at the recess 113.

  Further, the groove portion 441 includes a first protrusion 442 provided so as to protrude from the edge portion of the opening portion on the inner side surface of the groove portion 441 toward the edge portion of the opening portion on the outer side surface of the groove portion 441. . The first protrusion 442 includes a second protrusion 443 provided so as to protrude from the tip of the first protrusion 442 toward the bottom surface of the groove 441. The first protrusion 442 and the second protrusion 443 are used to prevent the bonding material 150 accommodated in the groove 441 from being discharged into the recess 113. The first projecting portion 442 is provided on the entire groove portion 441, and the projecting dimension of the first projecting portion 442 is formed in the range of 50 to 80% of the width of the groove portion 441. The second protrusion 443 is provided on the entire first protrusion 442, and the projecting dimension of the second protrusion is formed in a range of 10 to 50% of the depth of the groove 441. The first protrusion 442 and the second protrusion 443 are formed integrally with the lid member 440.

  The piezoelectric vibrator 400 according to the third modified example is provided with a first protrusion provided so as to protrude from the edge of the opening on the inner side surface of the groove 441 toward the edge of the opening on the outer side surface of the groove 441. 442 is provided, and the first protrusion 442 includes a second protrusion 443 that protrudes from the tip of the first protrusion 442 toward the bottom surface of the groove 441. With such a configuration, even if the bonding material 150 accommodated in the groove portion 441 is separated from the groove portion 441 due to an external impact or the like, the separated bonding material 150 is prevented from coming out of the groove portion 441 first. The protrusions 442 and the second protrusions 443 can be significantly suppressed. Accordingly, it is possible to further suppress the bonding material 150 separated from the inside of the groove portion 441 from entering the concave portion 113 and adhering to the piezoelectric vibration element 120, and the vibration can be further reduced. In addition, such a piezoelectric device 400 can stably obtain vibration of a desired frequency, and can have a good CI value.

  The present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the piezoelectric vibrator that is one form of the piezoelectric device is illustrated, but other piezoelectric devices such as a piezoelectric oscillator and a piezoelectric sensor may be used. In the above-described embodiment, the piezoelectric vibration element having a rectangular shape in plan view is exemplified as the piezoelectric vibration element mounted inside. However, a piezoelectric vibration element having an outer shape such as a tuning fork type or a circle may be provided.

100, 200, 300, 400 ... Piezoelectric vibrator (piezoelectric device)
DESCRIPTION OF SYMBOLS 110 ... Element mounting member 111 ... Board | substrate 112 ... Frame body 113 ... Recessed part 114 ... Electrode pad 115 ... External connection electrode pad 120 ... Piezoelectric vibration element 121 ... Piezoelectric element 122 ... excitation electrode 123 ... connection electrode 130 ... conductive adhesive 140, 240, 340, 440 ... lid member 141, 241, 341, 441 ... groove 150 ... bonding Material 342, 442 ... 1st projection part 443 ... 2nd projection part

Claims (5)

An element mounting member comprising: a rectangular substrate in plan view; and a frame provided on an upper surface of the substrate;
A piezoelectric vibration element mounted in a recess formed by the substrate and the frame;
A lid member having a rectangular plate shape in plan view, hermetically sealing the space in the concave portion by bonding the upper surface of the frame body with a bonding material;
Have
The lid member includes a groove provided along the edge of the portion of the lower surface of the lid member exposed to the recess when the lid member is joined to the upper surface of the frame. A piezoelectric device characterized by the above.   The piezoelectric device according to claim 1, wherein the groove is provided so as to form one ring.   3. The piezoelectric device according to claim 1, wherein the groove portion is provided at a position where a side surface on the outer side of the groove portion and a side surface on the concave portion side of the frame portion are flush with each other.   The first projection portion provided so as to protrude from the edge portion of the opening portion on the inner side surface of the groove portion toward the opening edge portion on the outer side surface of the groove portion. 3. The piezoelectric device described in one of the three.   5. The piezoelectric device according to claim 4, further comprising a second projecting portion provided so as to project from a tip of the first projecting portion toward a bottom surface side of the groove portion.

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