JP5508046B2 - Piezoelectric vibration element - Google Patents

Description

  The present invention relates to a piezoelectric vibration element used in an electronic device.

Conventionally, a piezoelectric vibrator or a piezoelectric oscillator is mounted as an electronic component in an electronic device such as a computer, a mobile phone, or a small information device. This piezoelectric vibrator or piezoelectric oscillator is used as a reference signal source or a clock signal source. In addition, piezoelectric vibrators and piezoelectric oscillators are equipped with a piezoelectric vibration element made of quartz.
Hereinafter, a piezoelectric vibration element using quartz as a piezoelectric material will be described.

FIG. 4 is an exploded perspective view showing an example of a piezoelectric vibrator using a conventional piezoelectric vibration element. As shown in FIG. 4, the conventional piezoelectric vibrator includes, for example, a piezoelectric vibration element 400, a lid member 440 having a recess, and an element having an external terminal G on the other main surface while having a recess on one main surface. It is comprised from the mounting member 450. FIG.
The conventional piezoelectric vibrating element 400 includes a piezoelectric vibrating piece 411 and a frame portion 412 surrounding the piezoelectric vibrating piece 411. Note that the piezoelectric vibrating element 400 includes a piezoelectric vibrating piece 411 and a frame portion 412 that are integrally formed. Further, it is schematically constituted by an excitation electrode 421, a connection electrode 422, and a conductive wiring pattern 423 provided on the surface of the piezoelectric vibrating piece 411 (see, for example, Patent Document 1).

  As shown in FIG. 4, the piezoelectric vibrating reed 411 is a flat plate having a substantially rectangular shape in plan view, and includes a vibrating portion 411 a provided with an excitation electrode 421, and a support portion 411 d connected to the vibrating portion 411 a and the frame portion 412. It is comprised by.

The vibration part 411a is formed in a substantially rectangular flat plate in plan view, and excitation electrodes 421 are formed on both main surfaces. The excitation electrodes 421 are provided on the main surface of the vibration part 411a so as to face each other.
The holding portion 411b is connected to one side of the frame portion 412 and the vibrating portion 411a.
In the frame portion 412, a metal film is provided in an annular shape on the edge sides of both main surfaces, and two pairs of connection electrodes 422 are provided in a portion connected to the vibrating portion 411 a inside the annular metal film. .
Each connection electrode 422 is electrically connected to the excitation electrode 421 provided on the main surface of the vibration part 411 a via the conductive wiring pattern 423.
The metal film provided on both main surfaces of the frame portion 412 is used, for example, for joining one side of the metal film to the lid member 440 having a recess, while the other metal film has the external terminal G. Used for connection with a base 450 having a recess.

JP 2007-96777 A

  However, in the piezoelectric vibration element having such a structure, the vibration generated in the vibration part 411a propagates to the frame part 412, and there is a risk of deteriorating temperature characteristics and CI values.

  Accordingly, an object of the present invention is to provide a piezoelectric vibration element that solves the above-described problems and improves temperature characteristics and CI values.

In order to solve the above-described problems, the present invention provides a piezoelectric vibration element that includes a holding portion and a vibration portion, and an electrode is formed on the vibration portion, and a frame portion that surrounds the piezoelectric vibration piece. A support portion that is provided on the holding portion and the frame portion of the piezoelectric vibrating piece and supports the piezoelectric vibrating piece, the support portion is a metal film, and the holding portion and the frame portion are at least 3 Two of the support parts are joined to a connection electrode provided on the holding part, and the other end part of the support part is connected to the support part. It is joined to the mounting electrode provided in the frame part, and the connection electrode and the mounting electrode are electrically connected via the support part .

In the present invention, the piezoelectric vibrating piece may have a shape selected from any one of a tuning fork type, a square plate type, and a round plate type.
Further, the present invention may be configured such that the piezoelectric vibrating piece vibrates in a vibration mode corresponding to any one of a bending vibration mode, a thickness-slip mode, and a contour mode.

Further, the present invention is a piezoelectric vibration element, comprising a holding portion and a vibration portion, a rectangular piezoelectric vibration piece having an electrode formed on the vibration portion, a frame portion surrounding the piezoelectric vibration piece, A support portion that is bonded to the holding portion and the frame portion of the piezoelectric vibrating piece and supports the piezoelectric vibrating piece; and the supporting portion is a metal film, and the holding portion is connected to a diagonal line of the piezoelectric vibrating piece. And the frame portion are supported in at least two locations, and two of the support portions are joined to a connection electrode provided on the holding portion at one end of the support portion, and the support portion The other end of the part is joined to a mounting electrode provided on the frame part, and the connection electrode and the mounting electrode are electrically connected via the support part. And

  According to such a piezoelectric vibrating element, the piezoelectric vibrating piece is configured by the holding portion and the vibrating portion, and an electrode is formed on the vibrating portion, the frame portion surrounding the piezoelectric vibrating piece, and the holding of the piezoelectric vibrating piece. And a support part that supports the piezoelectric vibrating piece, the support part is a metal film, and is configured to support the holding part and the frame part in at least three places. As a result, the piezoelectric vibrating reed is floated by the metal film that is the support part, making it difficult for vibration from the vibrating part to be transmitted to the frame part, reducing unnecessary vibrations that inhibit the vibration of the vibrating part, and reducing the temperature. The characteristics and CI value can be improved.

  In addition, even if the shape of the piezoelectric vibrating piece is one selected from a tuning fork type, a rectangular flat plate type, and a round flat plate type, the piezoelectric vibrating piece is floated by a metal film as a support portion Therefore, it is difficult for vibration from the vibration portion to be transmitted to the frame portion, generation of unnecessary vibration that hinders vibration of the vibration portion is reduced, and temperature characteristics and CI values can be improved.

  In addition, even if the piezoelectric vibrating piece is configured to vibrate in a vibration mode corresponding to any one of the bending vibration mode, the thickness-slip mode, and the contour mode, the piezoelectric vibrating piece is in a state of being floated by a metal film as a support portion. Therefore, it is difficult for vibration from the vibration part to be transmitted to the frame part, generation of unnecessary vibration that hinders vibration of the vibration part is reduced, and temperature characteristics and CI value can be improved.

  Further, according to the present invention, the piezoelectric vibration element includes a holding portion and a vibration portion, and a piezoelectric vibration piece having a square shape in which an electrode is formed on the vibration portion, a frame portion surrounding the piezoelectric vibration piece, and the piezoelectric vibration A support portion that is bonded to the holding portion and a frame portion of the piece to support the piezoelectric vibrating piece, the supporting portion is a metal film, and the holding portion and the Since the frame portion is supported by at least two places, the piezoelectric vibrating piece is floated by the metal film that is the support portion, and the vibration from the vibrating portion is difficult to be transmitted to the frame portion. Occurrence of unnecessary vibrations that hinder the temperature can be reduced, and temperature characteristics and CI values can be improved.

(A) is a perspective view which shows an example of the piezoelectric vibration element which concerns on embodiment of this invention, (b) is a schematic diagram which shows an example of the piezoelectric vibrator using the piezoelectric vibration element which concerns on embodiment of this invention. is there. It is a perspective view which shows an example of the modification of the piezoelectric vibrating element which concerns on embodiment of this invention, Comprising: (a) is a perspective view of the piezoelectric vibrating element in which the shape of a piezoelectric vibrating piece becomes a rectangle, (b) is piezoelectric FIG. 5C is a perspective view of a piezoelectric vibration element in which the shape of the vibration piece is circular, and FIG. 5C is a perspective view of the piezoelectric vibration element that is supported on a diagonal line with a square shape of the piezoelectric vibration piece. It is a perspective view which shows an example of the further modification of the piezoelectric vibration element which concerns on embodiment of this invention, Comprising: (a) shows an example of the state in which the support part was provided in both the main surfaces of a frame part and a holding part. It is a perspective view, (b) is a perspective view which shows an example of another piezoelectric vibrator. It is a perspective view which shows an example of the piezoelectric vibrator using the conventional piezoelectric vibration element.

  The best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate. Note that each component is exaggerated for easy understanding of the state.

  As shown in FIG. 1A, the piezoelectric vibrating element 101 according to the first embodiment of the present invention includes a piezoelectric vibrating piece 110a, an excitation electrode 121a and a connecting electrode 122a provided on the piezoelectric vibrating piece 110a. , 122b, a frequency adjusting electrode 123, a conductive wiring pattern 124a, a frame portion 130, and a support portion 140.

The piezoelectric vibrating piece 110a has a tuning fork shape, and includes a holding portion 111 serving as a base, a pair of vibrating portions 112 extending from the holding portion 111, an excitation electrode 121a, a connection electrode 122a, and a frequency adjustment electrode. 123a and a conductive wiring pattern 124a. The vibrating portion 112 is provided with excitation electrodes 121 having the same polarity on opposing planes.
The holding part 111 is a flat plate having a substantially rectangular shape in plan view. The vibration part 112 includes a first vibration arm part 112a and a second vibration arm part 112b. The first vibrating arm portion 112a and the second vibrating arm portion 112b extend in the same direction from one side of the holding portion 111, and the length of the first vibrating arm portion 112a and the second vibrating arm portion 112b. A groove GL is provided in each direction. The groove portion GL is formed on both main surfaces of the first vibrating arm portion 112a and the second vibrating arm portion 112b from the boundary portion with the holding portion 111 toward the tip of the vibrating portion 112, and in the length direction of the vibrating portion 112. Two are provided in parallel with a predetermined length. In such a piezoelectric vibrating piece 110a, the holding portion 111 and the vibrating portion 112 are integrated to form a tuning fork shape, and is manufactured by a photolithography technique and a chemical etching technique.

  The electrodes provided on the first vibrating arm portion 112a include an excitation electrode 121a and a frequency adjustment electrode 123a. The excitation electrode 121a is provided on one main surface including the inner surface of the groove portion GL of the first vibrating arm portion 112a and the other main surface including the inner surface of the groove portion GL of the first vibrating arm portion 112a. The excitation electrode 121a has a different polarity between the inner side surface of the first vibrating arm portion 112a facing the second vibrating arm portion 112b and the outer side surface of the first vibrating arm portion 112a facing the side surface. It is provided to become. The frequency adjusting electrode 123a is provided on both main surfaces of the distal end portion of the first vibrating arm portion 112a.

  The electrode provided on the second vibrating arm portion 112b includes an excitation electrode 121a and a frequency adjustment electrode 123a. The excitation electrode 121a is provided on one main surface including the inner surface of the groove portion GL of the second vibrating arm portion 112b and the other main surface including the inner surface of the groove portion GL of the second vibrating arm portion 112b. The excitation electrode 121a has a different polarity between the inner side surface of the second vibrating arm portion 112b facing the first vibrating arm portion 112a and the outer side surface of the second vibrating arm portion 112b facing the side surface. It is provided to become. The frequency adjusting electrode 123a is provided on both main surfaces of the distal end portion of the second vibrating arm portion 112a.

The holding portion 111 serving as a base is provided with connection electrodes 122a and 122b. The connection electrode 122a is provided from one corner end of the side opposite to the side where the vibrating portion 112 of the holding unit 111 is formed and from one main surface of the holding unit 111 to the other main surface. . Further, the connection electrode 122b is provided from the other corner end of the side opposite to the side where the vibrating portion 112 of the holding portion 111 is formed and from one main surface of the holding portion 111 to the other main surface. ing.
Further, the holding part 111 and the vibration part 112 are provided with a conductive wiring pattern 124a for electrically connecting predetermined electrodes.

  The connection electrode 122a is electrically connected to the excitation electrode 121a provided on one main surface of the first vibrating arm portion 112a by a conductive wiring pattern 124a provided on one main surface of the holding portion 111. And, it is electrically connected to the excitation electrode 121a provided on the outer side surface of the second vibrating arm portion 112b. In addition, the excitation electrode 121a provided on the outer side surface of the second vibrating arm portion 112b is connected to the excitation electrode 121a provided on the inner side surface of the second vibrating arm portion 112b via the frequency adjusting electrode 123a. Electrically connected. Furthermore, the excitation electrode 121a provided on one main surface of the first vibrating arm portion 112a is connected to the first vibrating arm portion by a conductive wiring pattern 124a provided on the inner side surface of the first vibrating arm portion 112a. It is electrically connected to an excitation electrode 121a provided on the other main surface of 112a.

  The connection electrode 122b is electrically connected to the excitation electrode 121a provided on the other main surface of the second vibrating arm portion 112b by a conductive wiring pattern provided on the other main surface of the holding portion 111, In addition, it is electrically connected to an excitation electrode 121a provided on the outer side surface of the first vibrating arm portion 112a. In addition, the excitation electrode 121a provided on the outer side surface of the first vibrating arm portion 112a is connected to the excitation electrode 121a provided on the inner side surface of the first vibrating arm portion 112a via the frequency adjusting electrode 123a. Electrically connected. Further, the excitation electrode 121a provided on the other main surface of the second vibrating arm portion 112a is connected to the first vibrating arm portion by a conductive wiring pattern 124a provided on the inner side surface of the second vibrating arm portion 112b. It is electrically connected to an excitation electrode 121a provided on one main surface of 112a.

  The excitation electrode 121a, the connection electrodes 122a and 122b, the frequency adjustment electrode 123a, and the conductive wiring pattern 124a are formed by photolithography and have a laminated structure in which an Au layer is provided on a Cr layer.

  When this tuning-fork type piezoelectric vibrating piece 110a is vibrated, an alternating voltage is applied to the connection electrodes 122a and 122b. When an electrical state after application is instantaneously captured, the excitation electrodes 121a provided on both main surfaces of the first vibrating arm portion 112a have a positive potential, and the excitation electrodes 121a provided on both side surfaces are negative. An electric field is generated from positive to negative. At this time, the excitation electrodes 121a on both main surfaces of the second vibrating arm portion 112b have a negative potential, and the excitation electrodes 121a provided on both side surfaces have a positive potential, the exciting electrode 121a of the first vibrating arm portion 112a. The polarity is opposite to the polarity generated in, and an electric field is generated from plus to minus. The electric field generated by the alternating voltage causes an expansion / contraction phenomenon in the first vibrating arm portion 112a and the second vibrating arm portion 112b, and a bending vibration mode having a resonance frequency set in the vibrating portion 112 is obtained. The resonance frequency can be adjusted by increasing or decreasing the amount of metal constituting the frequency adjusting electrode 123a provided on the tuning-fork type piezoelectric vibrating piece 110a.

The frame part 130 is formed in, for example, a square annular state, and is provided so as to surround the piezoelectric vibrating piece 110a.
For example, the frame portion 130 is provided with mounting electrodes 131 at two adjacent corners of the four corners in an annular state of a square shape. The mounting electrode 131 includes a first mounting electrode 131a and a second mounting electrode 131b having different polarities, and is provided at a position facing the connection electrodes 122a and 122b provided on the piezoelectric vibrating piece 110a. It has been.
Further, the mounting electrode 131 is provided so as to be electrically connected to the front and back main surfaces of the frame portion 130.

The support portion 140 is provided on the holding portion 111 and the frame portion 130 of the piezoelectric vibrating piece 110a and plays a role of supporting the piezoelectric vibrating piece 110a. The support part 140 is a metal film, and supports the holding part 111 and the frame part 130 at least at three locations.
At this time, one of the three support portions 140 is electrically connected to, for example, the connection electrode 122a provided on the piezoelectric vibrating piece 110a and the mounting electrode 131a provided on the frame portion 130. ing. Of the remaining two support portions 140, one support portion 140 is electrically connected to, for example, the connection electrode 122b provided on the piezoelectric vibrating piece 110a and the mounting electrode 131b provided on the frame portion 130. doing.
The support 140 may be a metal film provided by electrolytic plating or electroless plating. For example, the support part 140 can be comprised by gold plating.

  Here, as shown in FIG. 1B, the piezoelectric vibration element 101 according to the embodiment of the present invention is, for example, a piezoelectric vibrator that is mounted on an element mounting member S having a recess and is hermetically sealed by a lid member F. Can be used. For example, in the piezoelectric vibration element 101, the mounting electrodes 131 a and 131 b provided on the frame part 130 are joined to a mounting pad (not shown) provided in the recess of the element mounting member S via the conductive adhesive D. Thus, it is mounted on the element mounting member S. In this state, the lid member F is joined to the element mounting member S so as to seal the recess. Thereby, the piezoelectric vibration element 101 according to the embodiment of the present invention is hermetically sealed in the recess, and is electrically connected to the element mounting member S so as to be able to oscillate at a predetermined frequency.

  Such a piezoelectric vibrating element 101 includes a holding unit 111 and a vibrating unit 112, and includes a piezoelectric vibrating piece 110a in which an electrode is formed on the vibrating unit 112, a frame unit 130 surrounding the piezoelectric vibrating piece 110a, and a piezoelectric vibrating piece. 110a, and a support part 140 that is provided on the holding part 111 and the frame part 130 and supports the piezoelectric vibrating piece 110a. The support part 140 is a metal film, and the holding part 111 and the frame part 130 are provided at least in three places. Since it is configured to be supported, the piezoelectric vibrating piece 110a is floated by the metal film that is the support portion 140, and the vibration from the vibration portion 112 is not easily transmitted to the frame portion 130, and the vibration of the vibration portion 112 is inhibited. Generation of unnecessary vibrations is reduced, and temperature characteristics and CI values can be improved.

(Modification of the embodiment)
In the piezoelectric vibrator 101, the shape of the piezoelectric vibrating piece used in the piezoelectric vibrating element of the present invention can be modified. For example, as shown in FIG. 2A, the piezoelectric vibrating piece 110b has a rectangular plate shape in outer shape, and excitation electrodes 121c are formed on both main surfaces. Such a piezoelectric vibrating piece 110b vibrates in a thickness sliding mode.
In this case, in the piezoelectric vibrating piece 110b, the portion where the excitation electrode 121c is provided becomes the vibrating portion 112c, and the other portion becomes the holding portion 111b. The holding portion 111b is provided with two pairs of connection electrodes 122c having different polarities. Each connection electrode 122c is electrically connected to one excitation electrode 121c via a conductive wiring pattern 124b.

As another example, as shown in FIG. 2B, the piezoelectric vibrating piece 110c has a round plate shape in outer shape, and excitation electrodes 121d are formed on both main surfaces.
In this case, in the piezoelectric vibrating piece 110c, the portion where the excitation electrode 121d is provided becomes the vibrating portion 112d, and the other portion becomes the holding portion 111c. The holding portion 111c is provided with two pairs of connection electrodes 122d having different polarities. Each connection electrode 122d is electrically connected to one excitation electrode 121d via a conductive wiring pattern 124c.

As another example, as shown in FIG. 2C, the piezoelectric vibrating piece 110d has an outer shape of a rectangular flat plate shape, and excitation electrodes 121e are formed on both main surfaces. Such a piezoelectric vibrating piece 110d vibrates in a contour mode.
In this case, in the piezoelectric vibrating piece 110d, the portion where the excitation electrode 121e is provided becomes the vibrating portion 112e, and the other portion becomes the holding portion 111d. The holding portion 111d is provided with two pairs of connection electrodes 122e so as to be positioned on a diagonal line and to have different polarities. Each connection electrode 122e is electrically connected to one excitation electrode 121e via a conductive wiring pattern 124d.
In the case of the piezoelectric vibrating piece 110d configured in the contour mode, the two support portions 140 can be configured to be connected to the two connection electrodes 122e on the diagonal line.

  Even if the piezoelectric vibrating reeds 110b, 110c, and 110d are configured as described above, the vibrations from the vibrating portions 112c and 112d are not easily transmitted to the frame portion 130 because they are floated by the metal film that is the support portion 140. Thus, generation of unnecessary vibrations that hinder the vibrations of the vibration parts 112c and 112d is reduced, and the temperature characteristics and the CI value can be improved.

(Further modification of the embodiment)
The shape of the piezoelectric vibrating piece used in the piezoelectric vibrating element of the present invention can be further modified. For example, as shown in FIG. 3A, the piezoelectric vibrating piece 110e used in the piezoelectric vibrating element 101b of the present invention is formed in a tuning fork shape and is supported by the frame portion 130 by five support portions 140. .
The support portion 130 is provided at three locations on one main surface of the piezoelectric vibrating piece 110e and the frame portion 130, and is provided at two locations on the other main surface.
In addition, the respective support portions 140 are provided with their positions shifted so as not to face each other. This is because, when the support portion 140 on one main surface and the support portion 140 on the other main surface are provided to face each other, the etching technology is used when the shapes of the piezoelectric vibrating piece 110e and the frame portion 130 are formed by the etching technology. Therefore, there is a possibility that the piezoelectric material to be removed cannot be removed. Therefore, the support part 140 of one main surface and the support part 140 of the other main surface are provided so as to be shifted from each other so as not to face each other.
Even if the piezoelectric vibration element 101b is configured as described above, the vibration from the vibration parts 112c and 112d is not easily transmitted to the frame part 130 because it is floated by the metal film that is the support part 140, and the vibration part 112c. , 112d can be prevented from generating unnecessary vibrations, and temperature characteristics and CI values can be improved.

In the case of such a piezoelectric vibration element 101b, as shown in FIG. 3B, a piezoelectric vibrator having a structure in which the piezoelectric vibration element 101b is sandwiched between the element mounting member S and the lid member F may be used.
In this case, the element mounting member S and the lid member F are each formed with a recess so as to surround the vibration part of the piezoelectric vibrating piece, and the mounting electrode 131 provided in the frame part is located in the recess. Is provided.
Even with such a piezoelectric vibrator, the piezoelectric vibration element 101b of the present invention can be used.

In addition, although embodiment of this invention was described, this invention can be changed suitably.
For example, a piezoelectric material such as quartz or piezoelectric ceramic can be used for the piezoelectric vibration element. In addition, the frequency adjusting electrode may be separately thickened using a metal material such as Pt (palladium) or Au (gold).
In addition, as described above, the piezoelectric vibration element of the present invention uses the predetermined element mounting member having a recess and a lid member, the piezoelectric vibration element of the present invention is mounted in the recess, and the recess is hermetically sealed with the lid member. A piezoelectric vibrator may be configured.
The piezoelectric vibration element of the present invention may be a piezoelectric oscillator by connecting an integrated circuit element having at least an oscillation circuit to the piezoelectric vibrator.

DESCRIPTION OF SYMBOLS 101 Piezoelectric vibration element 110a Piezoelectric vibration piece 111 Holding part 112 Vibration part 121a Excitation electrode 112a First vibration arm part 112b Second vibration arm part 122a, 122b Connection electrode 123 Frequency adjustment electrode 124a Conductive wiring pattern 130 Frame part 131 Electrode for mounting 140 Support part

Claims (4)

A piezoelectric vibrating piece that includes a holding portion and a vibrating portion, and an electrode is formed on the vibrating portion;
A frame portion surrounding the piezoelectric vibrating piece;
A support portion provided on the holding portion and the frame portion of the piezoelectric vibrating piece to support the piezoelectric vibrating piece;
The support part is a metal film, and supports the holding part and the frame part in at least three places ;
Two of the support portions are mounted such that one end portion of the support portion is joined to a connection electrode provided in the holding portion, and the other end portion of the support portion is provided in the frame portion. It is joined with the electrode for
The piezoelectric vibration element, wherein the connection electrode and the mounting electrode are electrically connected via the support portion .   2. The piezoelectric vibration element according to claim 1, wherein the piezoelectric vibrating piece has a shape selected from any one of a tuning fork type, a square plate type, and a round plate type.   2. The piezoelectric vibration element according to claim 1, wherein the piezoelectric vibration piece is configured to vibrate in a vibration mode corresponding to any one of a bending vibration mode, a thickness-slip mode, and a contour mode. A square-shaped piezoelectric vibrating piece composed of a holding portion and a vibrating portion, and having an electrode formed on the vibrating portion;
A frame portion surrounding the piezoelectric vibrating piece ;
Wherein joined to said holding portion and the frame portion of the piezoelectric vibrating piece and a support portion supporting the piezoelectric vibrating piece,
The support part is a metal film, and supports the holding part and the frame part in at least two places so as to connect the diagonal lines of the piezoelectric vibrating piece ;
Two of the support portions are mounted such that one end portion of the support portion is joined to a connection electrode provided in the holding portion, and the other end portion of the support portion is provided in the frame portion. It is joined with the electrode for
The piezoelectric vibration element, wherein the connection electrode and the mounting electrode are electrically connected via the support portion .

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