JP2016072638A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device which properly detects a temperature and enables downsizing.SOLUTION: A piezoelectric device includes: a base member 10 provided with connection terminals; a cover member 20 covering the base member; an oscillation member 30 disposed in a space between the base member and the cover member; and a joint material 40 which joins the base member to the cover member. The joint material 40 contains a conductive material having thermosensitivity and is electrically connected with the connection terminals 15a, 15b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piezoelectric device including an oscillation member.

  A crystal resonator, which is one of piezoelectric devices, is small and light, and is therefore used as a frequency and time reference source in portable electronic devices. In the crystal resonator, a crystal piece that is an oscillation member is disposed in a sealed space between a base member and a cover member that covers the base member.

  By the way, the crystal resonator has a predetermined frequency temperature characteristic, and the thermistor is used for temperature detection for canceling the frequency temperature property of the crystal resonator and operating the crystal resonator stably. . In Patent Document 1 below, a crystal piece and a thermistor are arranged in a sealed space, and the operating temperature of the crystal resonator is detected.

JP 2008-205938 A

  Along with the downsizing of electronic equipment and the like, there is a demand for further downsizing of a crystal resonator that is a piezoelectric device. However, since the thermistor described above is mounted as an individual component, the sealed space cannot be narrowed, which hinders downsizing of the piezoelectric device.

  Therefore, the present invention has been made in view of these points, and an object of the present invention is to provide a piezoelectric device that can detect a temperature appropriately and can be miniaturized.

  In the first aspect of the present invention, a base member provided with a connection terminal, a cover member covering the base member, and an oscillation member disposed in a space formed by the base member and the cover member; And a bonding material that bonds the base member to the cover member, and the bonding material includes a temperature-sensitive conductive material and is electrically connected to the connection terminal. I will provide a.

  In the above piezoelectric device, the bonding material may be positioned so as to surround the oscillation member attached to the base member. The base member may be made of a non-conductive hard material, and the cover member may be made of a hard material containing metal.

    The base member is joined to the cover member, a joint surface, a terminal placement surface on the opposite side of the joint surface, the connection terminal is placed, the joint surface, and the terminal placement A path for electrically connecting the surfaces may be provided, and the bonding material may be electrically connected to the connection terminal via the path. The conductive material may include a material that composes a thermistor. The conductive material may include barium titanate.

  According to the present invention, it is possible to provide a piezoelectric device that can detect a temperature appropriately and can be miniaturized.

FIG. 3 is an exploded perspective view illustrating an example of a configuration of a vibrator 1 according to the first embodiment. 3 is a side view of the vibrator 1. FIG. FIG. 3 is a diagram showing an equivalent circuit of a vibrator 1. 4 is a schematic diagram for explaining an example of a configuration of a bonding material 40. FIG. It is a figure for demonstrating the connection relation of the joining material 40 and two connection terminals 15a and 15c. FIG. 6 is an exploded perspective view illustrating an example of a configuration of a vibrator 100 according to a second embodiment. 3 is a side view of the vibrator 100. FIG. It is a figure which shows an example of a structure of the vibrator | oscillator 200 which concerns on a modification.

<First Embodiment>
With reference to FIGS. 1 to 3, a configuration of a vibrator as an example of the piezoelectric device according to the first embodiment of the present invention will be described.

  FIG. 1 is an exploded perspective view showing a case where a through hole is used for electrical connection between a conductive bonding material having temperature sensitivity and a connection terminal as an example of the configuration of the vibrator 1 according to the first embodiment. is there. FIG. 2 is a side view of the vibrator 1. FIG. 3 is a diagram showing an equivalent circuit of the vibrator 1. 2A is a right side view of the vibrator 1 viewed from the X1 direction in FIG. 1, and FIG. 2B is a left side view of the vibrator 1 viewed from the X2 direction in FIG.

  The vibrator 1 is, for example, a crystal vibrator, and is used as a reference clock of a microcomputer as a reference source of frequency and time in a portable electronic device.

  As shown in FIG. 1, the vibrator 1 includes a base member 10, a cover member 20, an oscillation member 30, and a bonding material 40. Below, it demonstrates for every structural member.

(Base member 10)
The base member 10 is a container made of, for example, a hard material of multilayer ceramic and having a recess 11 formed in the center. The base member 10 accommodates the oscillation member 30 in the space in the recess 11. As illustrated in FIGS. 1 and 2, the base member 10 includes a joint surface 12, a terminal arrangement surface 14, connection terminals 15 a to 15 d, and through holes 16 a and 16 b.

  The bonding surface 12 is the upper surface of the base member 10 and is bonded to the cover member 20 via the bonding material 40. The terminal arrangement surface 14 is a lower surface of the base member 10 located on the opposite side to the bonding surface 12.

  The connection terminals 15 a to 15 d are arranged on the terminal arrangement surface 14. Specifically, as shown in FIGS. 2A and 2B, the four connection terminals 15 a to 15 d are positioned at the corners of the terminal arrangement surface 14. The four connection terminals 15a to 15d are connected to a circuit that drives the vibrator 1, for example, the above-described mounting board of the microcomputer.

  The through holes 16 a and 16 b are through holes penetrating from the bonding surface 12 to the terminal arrangement surface 14. For example, copper plating is applied to the inner periphery of the through hole. The through holes 16 a and 16 b are paths that electrically connect the bonding surface 12 and the terminal arrangement surface 14. Specifically, the through hole 16a electrically connects the joint surface 12 and the connection terminal 15a of the terminal arrangement surface 14, and the through hole 16b electrically connects the joint surface 12 and the connection terminal 15c.

(Cover member 20)
The cover member 20 is a hard flat plate made of metal or ceramic, for example, and covers the base member 10. Specifically, the cover member 20 closes the opening of the recess 11 of the base member 10 to make the inside of the recess 11 a sealed space. The lower surface 22 of the cover member 20 is bonded to the bonding surface 12 of the base member 10.

(Oscillation member 30)
The oscillation member 30 is disposed in a space formed by the base member 10 and the cover member 20. The oscillation member 30 is a crystal piece, for example. The oscillation member 30 is fixed to the bottom of the recess 11 with a conductive adhesive. As shown in FIG. 3, the oscillating member 30 is connected to the connection terminal 15 b and the connection terminal 15 d that are located diagonally on the terminal arrangement surface 14. Although not shown in FIG. 2, the oscillation member 30 is connected to the connection terminal 15b and the connection terminal 15d through a through hole formed in the bottom of the recess 11.

(Bonding material 40)
The bonding material 40 bonds the bonding surface 12 of the base member 10 and the lower surface 22 of the cover member 20. Such a bonding material 40 has a function as a sealing material for sealing the space in the recess 11. Thereby, the space in the recessed part 11 can be kept airtight.

  As shown in FIG. 1, the bonding material 40 includes surfaces (hereinafter also referred to as long surfaces) 12 a and 12 b along the longitudinal direction (Y direction) of the bonding surface 12, and the short direction (X direction) of the bonding surface 12. Are applied to surfaces (hereinafter also referred to as short surfaces) 12c and 12d. That is, the bonding material 40 is positioned so as to surround the oscillation member 30 attached to the base member 10. Further, the bonding material 40 is a conductive adhesive in the present embodiment.

  FIG. 4 is a schematic diagram for explaining an example of the configuration of the bonding material 40. As shown in FIG. 4, the bonding material 40 is a mixture of a temperature-sensitive conductive material 41 and a binder material 42 made of a bonding material.

  The conductive material 41 includes thermistor particles that are a material constituting the thermistor. The thermistor particles are obtained by pulverizing a thermistor prepared by high-temperature firing. As shown in FIG. 4, the thermistor particles are distributed so as to contact each other inside the bonding material 40. The thermistor particles may include, for example, barium titanate. In a thermistor using barium titanate, the resistance value of barium titanate rapidly increases when a specific temperature is exceeded, so that a temperature change can be easily detected.

  The binder material 42 has non-conductivity and is made of, for example, an epoxy resin. However, the present invention is not limited to this, and the binder material 42 may be made of a glass-based material.

  FIG. 5 is a diagram for explaining a connection relationship between the bonding material 40 and the two connection terminals 15a and 15c. As illustrated in FIG. 5, the bonding material 40 forms a conductive path 45 that electrically connects the connection terminal 15 a and the connection terminal 15 c that are located diagonally on the terminal arrangement surface 14. Specifically, the bonding material 40 is electrically connected to the connection terminal 15a and the connection terminal 15c through the through holes 16a and 16b (FIG. 2). Further, the bonding material 40 functions as a thermistor 46 in the conductive path 45 as shown in FIG. Thereby, the temperature information (for example, change in resistance value) detected by the thermistor 46 is transmitted to the outside through the connection terminal 15a and the connection terminal 15c.

  In the above description, copper plating is applied to the inner periphery of the through holes 16a and 16b. However, the present invention is not limited to this. For example, the bonding material 40 may be filled in the through holes 16a and 16b. Even in such a case, the bonding material 40 is electrically connected to the connection terminal 15a and the connection terminal 15c.

  In FIG. 5, the conductive path 45 is formed on the two long surfaces 12a and 12b and the two short surfaces 12c and 12d. However, the present invention is not limited to this. For example, while the conductive path 45 is formed on the long surface 12b and the short surface 12d, the conductive path may not be formed on the long surface 12a and the short surface 12c. For this purpose, a bonding material 40 having temperature sensitivity is applied to the long surface 12b and the short surface 12d, and a non-conductive bonding material is applied to the long surface 12a and the short surface 12c.

(Effects of the first embodiment)
In the first embodiment, the bonding material 40 for bonding the base member 10 and the cover member 20 includes a conductive material having a temperature sensitivity, and the conductive path 45 that electrically connects the two connection terminals 15a and 15c. Forming.
As a result, the bonding material 40 has a function of sealing the space (recess 11) in which the oscillation member 30 is disposed and a function of detecting the temperature around the oscillation member 30. In such a case, it is not necessary to dispose a thermistor as an individual component in the recess 11 and the recess 11 can be narrowed, so that further reduction in size of the vibrator 1 can be realized.

<Second Embodiment>
The configuration of the vibrator according to the second embodiment will be described with reference to FIGS. FIG. 6 is an exploded perspective view illustrating an example of the configuration of the vibrator 100 according to the second embodiment. FIG. 7 is a side view of the vibrator 100. 7A is a right side view of the vibrator 100 viewed from the X1 direction in FIG. 6, and FIG. 7B is a left side view of the vibrator 100 viewed from the X2 direction in FIG.

  In the second embodiment, the shapes of the base member 110 and the cover member 120 are different from those of the first embodiment. The base member 110 is a flat plate member as shown in FIG. 6, and no recess is formed. The oscillation member 130 is fixed to the upper surface 112 of the base member 110. The cover member 120 is a member having a reverse U-shaped cross section in a plane orthogonal to the longitudinal direction (Y direction), and has a space inside. Thereby, a space for arranging the oscillation member 130 is formed between the cover member 120 and the base member 110.

  The joining material 140 joins the upper surface 112 of the base member 110 and the flange portion 122 of the cover member 120. In the second embodiment, the bonding material 140 also includes a conductive material having a temperature sensitivity, and forms a conductive path that connects the two connection terminals 115 a and 115 c arranged on the terminal arrangement surface 114. The connection terminals 115a and 115c are electrically connected to the bonding material 140 through the through holes 116a and 116b (FIG. 7), respectively. Since the configuration other than the above is the same as that of the first embodiment, detailed description thereof is omitted.

  Also in the second embodiment, the bonding material 140 has a function of sealing a space in which the oscillation member 130 is disposed and a function of detecting the temperature around the oscillation member 130. In such a case, it is not necessary to arrange a thermistor in the space formed by the base member 110 and the cover member 120, and the space can be narrowed, so that further reduction in size of the vibrator 100 can be realized.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

In the above description, the connection between the bonding material and the connection terminal is performed through the through-hole. However, the present invention is not limited to this. It may be performed via.
In the above description, the base member is made of ceramics, but is not limited thereto, and may be made of, for example, crystal, glass, resin, or plastic. The base member is preferably made of a hard material that can secure an electrical path between the connection terminal and the bonding material. Similarly, the cover member may be made of a hard material made of quartz, glass, resin, or plastic.

  FIG. 8 is a diagram illustrating an example of the configuration of the vibrator 200 according to the modification. The vibrator 200 includes a base member 210 made of quartz, a cover member 220, and an oscillation member 230. In the oscillation member 230, a side wall of the vibrator is formed so as to surround the oscillation unit 232 on the center side. As in the first embodiment, the oscillation member 230 and the cover member 220 are bonded together by a conductive bonding material 240 having temperature sensitivity. Further, the bonding material 240 is electrically connected to the connection terminal 215 of the base member 210. As a result, the bonding material 240 detects the temperature around the oscillation unit 232.

1, 100, 200 Vibrator 10, 110, 210 Base member 12 Joint surface 14 Terminal arrangement surface 15a-15d Connection terminal 16a, 16b Through hole 20, 120, 220 Cover member 30, 130, 230 Oscillating member 40, 140, 240 Join Material 41 Conductive material 42 Binder material 45 Conductive path

Claims (6)

A base member provided with a connection terminal;
A cover member covering the base member;
An oscillating member disposed in a space formed by the base member and the cover member;
A bonding material bonding the base member and the cover member;
With
The bonding material includes a piezoelectric material that includes a temperature-sensitive conductive material and is electrically connected to the connection terminal. The bonding material is positioned so as to surround the oscillation member attached to the base member.
The piezoelectric device according to claim 1. The base member is made of a non-conductive hard material,
The cover member is made of a hard material containing metal,
The piezoelectric device according to claim 1 or 2. The base member is
A joining surface joined to the cover member;
A terminal arrangement surface located on the side opposite to the bonding surface, on which the connection terminals are arranged;
A path for electrically connecting the joint surface and the terminal arrangement surface;
The bonding material is electrically connected to the connection terminal via the path.
The piezoelectric device according to any one of claims 1 to 3. The conductive material includes a material constituting a thermistor,
The piezoelectric device according to any one of claims 1 to 4. The conductive material includes barium titanate,
The piezoelectric device according to claim 1.