Vibration device

Abstract

This invention provides a vibration device that prevents performance degradation due to contact between the excitation electrode and the package. [Solution] The vibration device 1 comprises an integrally formed base substrate 2, a lid 3 joined to the base substrate 2 to form a housing space 4, and a vibration element 30 housed in the housing space 4. The base substrate 2 includes a first mounted electrode 11 and a second mounted electrode 12 provided on the inner bottom surface 6 and joined to one end 17 of the vibration element 30, and a pillow portion 13 provided on the inner bottom surface 6 at a position that overlaps with the other end 18 of the vibration element 30 in a plan view. When the direction from the other end 18 to the one end 17 of the vibration element 30 is taken as the first direction, the pillow portion 13 includes a thickened portion 14 protruding from the inner bottom surface 6 and an inclined portion 15 extending from the thickened portion 14 toward the first direction and connecting the thickened portion 14 and the inner bottom surface 6.

Description

Technical Field

[0001] The present invention relates to a vibration device.

Background Art

[0002] For example, Patent Document 1 describes a piezoelectric device having a structure in which a piezoelectric vibrator is supported in a cantilever state on a pad in a recess of a package and the recess is hermetically sealed with a lid. The inner bottom surface of the recess of the package is an inclined surface, and one end of the piezoelectric vibrator is supported in a cantilever state on a pad provided on the lower side through a conductive adhesive, and the other end of the piezoelectric vibrator is disposed opposite to the upper side of the inner bottom surface with a minute gap therebetween.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the piezoelectric device described in Patent Document 1 is premised on making the entire inner bottom surface an inclined surface in the prior art, the overall inclination is gentle. Therefore, due to undulations of the ceramic layer or the like, there is a risk that the excitation electrode of the vibrator comes into contact with the package, causing characteristic deterioration.

Means for Solving the Problems

[0005] The vibration device comprises an integrally formed base substrate, a lid joined to the base substrate to form a housing space, and a vibration element housed in the housing space, wherein the base substrate includes a first mounted electrode and a second mounted electrode provided on its inner bottom surface and joined to one end of the vibration element, and a pillow portion provided on the inner bottom surface at a position overlapping with the other end of the vibration element in a plan view, and when the direction from the other end of the vibration element toward the one end is defined as the first direction, the pillow portion includes a thickened portion protruding from the inner bottom surface and an inclined portion extending from the thickened portion toward the first direction and connecting the thickened portion and the inner bottom surface. [Brief explanation of the drawing]

[0006] [Figure 1] A plan view showing the schematic structure of the vibration device according to the first embodiment. [Figure 2] Cross-sectional view along line AA in Figure 1. [Figure 3] A plan view showing the schematic structure of the vibration device according to the second embodiment. [Figure 4] Cross-sectional view along line AA in Figure 3. [Figure 5] Enlarged view of section B in Figure 4. [Figure 6] A plan view showing the schematic structure of the vibration device according to the third embodiment. [Figure 7] Cross-sectional view along line AA in Figure 6. [Modes for carrying out the invention]

[0007] 1. First Embodiment First, the vibration device 1 according to the first embodiment will be described with reference to Figures 1 and 2. In Figure 1, the lid 3 is shown removed for the convenience of explaining the internal structure of the vibration device 1. Also, in Figures 1 and 2, the wiring that electrically connects the first mounted electrode 11 and the second mounted electrode 12 to the external terminal 20 provided on the lower surface of the base substrate 2 is not shown.

[0008] For the sake of clarity, the following plan and cross-sectional views illustrate three mutually orthogonal axes: the X-axis, Y-axis, and Z-axis. The direction along the X-axis is referred to as the "X-direction," the direction along the Y-axis as the "Y-direction," and the direction along the Z-axis as the "Z-direction." The tip of the arrow in each axial direction is also referred to as the "positive side," and the base end as the "negative side." In this embodiment, the negative X-direction is the first direction.

[0009] As shown in Figures 1 and 2, the vibration device 1 according to this embodiment comprises an integrally formed base substrate 2, a lid 3 joined to the base substrate 2 to form a housing space 4, and a vibration element 30 housed in the housing space 4.

[0010] The base substrate 2, made of ceramic or the like, and the lid 3, made of metal, ceramic, glass or the like, are joined together via a sealing ring, low-melting-point glass, or other joining member 7.

[0011] The base substrate 2 is provided with a recess 5 on the upper surface that is recessed on the side opposite to the lid 3, and includes a first mounted electrode 11 and a second mounted electrode 12 provided on the inner bottom surface 6 of the recess 5 and joined to one end 17 of the vibrating element 30, and a pillow portion 13 provided on the inner bottom surface 6 at a position that overlaps with the other end 18 of the vibrating element 30 in a plan view, and is integrally formed.

[0012] When the direction from the other end 18 to the one end 17 of the vibrating element 30 is defined as the first direction (in Figures 1 and 2, this is the negative X direction), the pillow portion 13 includes a thickened portion 14 protruding from the inner bottom surface 6, and an inclined portion 15 extending from the thickened portion 14 toward the first direction, the negative X direction, and connecting the thickened portion 14 and the inner bottom surface 6. In other words, the thickness of the inclined portion 15 gradually decreases toward the first direction, the negative X direction, from the thickened portion 14.

[0013] The base substrate 2 is provided with a pillow portion 13 having a thick portion 14 and an inclined portion 15 whose thickness gradually decreases in the minus X direction which is the first direction, at a position overlapping the other end portion 18 of the vibration element 30. Therefore, when an impact in the Z direction is applied, the displacement of the other end portion 18 of the vibration element 30 can be suppressed by the other end portion 18 contacting the thick portion 14. Further, since the inclined portion 15 is arranged at a position overlapping the excitation electrode 32 of the vibration element 30, it becomes difficult for the excitation electrode 32 of the vibration element 30 to contact the base substrate 2, and characteristic deterioration due to the excitation electrode 32 contacting the base substrate 2 can be prevented.

[0014] Further, since the pillow portion 13 includes the inclined portion 15, even in the case of the vibration element 30 having a short length in the X direction, the displacement of the other end portion 18 can be suppressed by the other end portion 18 contacting the inclined portion 15, and characteristic deterioration due to the excitation electrode 32 contacting the base substrate 2 can be prevented.

[0015] The lengths L1 of the first mounting electrode 11 and the second mounting electrode 12 along the minus X direction which is the first direction are smaller than the length L2 of the pillow portion 13 along the minus X direction which is the first direction. That is, they are in the relationship of L1 < L2. By making L2 larger than L1, when mounting the vibration element 30 on the first mounting electrode 11 and the second mounting electrode 12, even if a mounting position shift occurs, the other end portion 18 of the vibration element 30 can be arranged at a position overlapping the pillow portion 13.

[0016] Incidentally, the pillow portion 13 provided on the inner bottom surface 6 of the base substrate 2 can be formed by pressing while heating a ceramic green sheet which is the material of the base substrate 2 using a mold.

[0017] The vibration element 30 includes a flat vibration substrate 31, excitation electrodes 32 provided on two surfaces that are in a front-back relationship of the vibration substrate 31, a pad electrode 34 provided on the lower surface, a lead electrode 33 that electrically connects the excitation electrode 32 and the pad electrode 34, and a side surface electrode 35 that electrically connects the lead electrode 33 provided on the upper surface and the pad electrode 34 provided on the lower surface. The vibration element 30 has a cantilever structure in which a pad electrode 34 provided on the lower surface of one end portion 17 is joined and fixed to the upper surfaces of the first mounting electrode 11 and the second mounting electrode 12 via a joining member 40.

[0018] Note that, as the vibration element 30, for example, a crystal oscillator, other piezoelectric oscillators, MEMS (Micro Electro Mechanical Systems) oscillators, etc. can be used. As the material of the vibration substrate 31, piezoelectric materials such as piezoelectric ceramics such as quartz and lead titanate zirconate, or silicon semiconductor materials, etc. can be used.

[0019] The vibration device 1 of the present embodiment is provided with a pillow portion 13 including a thick portion 14 and an inclined portion 15 whose thickness gradually decreases from the thick portion 14 in the minus X direction which is the first direction, at a position overlapping the other end portion 18 of the vibration element 30 on the base substrate 2. Therefore, when an impact in the Z direction is applied, the displacement of the other end portion 18 can be suppressed by the other end portion 18 contacting the thick portion 14. Further, since the inclined portion 15 is arranged at a position overlapping the excitation electrode 32 of the vibration element 30, it becomes difficult for the excitation electrode 32 of the vibration element 30 to contact the base substrate 2, and it is possible to prevent deterioration of characteristics due to the excitation electrode 32 contacting the base substrate 2.

[0020] 2. Second Embodiment Next, the vibration device 1a according to the second embodiment will be described with reference to FIGS. 3, FIGS. 4, and FIGS. 5. Note that, for convenience of explanation, FIG. 3 shows a state in which the lid body 3 is removed. Also, in FIGS. 3 and FIGS. 4, illustration of wiring that electrically connects the first mounting electrode 11 and the second mounting electrode 12 and the external terminal 20 provided on the lower surface of the base substrate 2a is omitted.

[0021] The vibration device 1a of this embodiment is the same as the vibration device 1 of the first embodiment, except that the structure of the base substrate 2a is different from that of the vibration device 1 of the first embodiment. The explanation will focus on the differences from the first embodiment described above, and similar matters will be omitted.

[0022] As shown in Figures 3, 4, and 5, the vibration device 1a comprises a base substrate 2a, a lid 3 joined to the base substrate 2a to form a housing space 4, and a vibration element 30 housed in the housing space 4.

[0023] The base substrate 2a has a recess 5 that is recessed from the top surface on the side opposite to the lid 3, and includes a first mounted electrode 11 and a second mounted electrode 12 provided on the inner bottom surface 6 of the recess 5 and joined to one end 17 of the vibrating element 30, and a pillow portion 13a provided on the inner bottom surface 6 at a position that overlaps with the other end 18 of the vibrating element 30 in a plan view.

[0024] The pillow portion 13a includes a thickened portion 14a protruding from the inner bottom surface 6, and an inclined portion 15a extending from the thickened portion 14a in the first direction, the minus X direction, and connecting the thickened portion 14a and the inner bottom surface 6. The thickened portion 14a and the inclined portion 15a are connected by a curved surface 16. Since the thickened portion 14a and the inclined portion 15a are connected by a curved surface 16, damage to the vibration substrate 31 caused by the other end 18 of the vibration element 30 contacting the curved surface 16 when an impact is applied in the Z direction can be further reduced.

[0025] This configuration reduces damage to the vibration substrate 31 due to impact, and also provides the same effects as the first embodiment.

[0026] 3. Third Embodiment Next, the vibration device 1b according to the third embodiment will be described with reference to Figures 6 and 7. For the sake of explanation, Figure 6 shows the device with the cover 3 removed. Also, in Figures 6 and 7, the wiring that electrically connects the first mounted electrode 11 and the second mounted electrode 12 to the external terminal 20 provided on the lower surface of the base substrate 2b is not shown.

[0027] The vibration device 1b of this embodiment is the same as the vibration device 1 of the first embodiment, except that the structure of the base substrate 2b is different from that of the vibration device 1 of the first embodiment. The explanation will focus on the differences from the first embodiment described above, and similar matters will be omitted.

[0028] As shown in Figures 6 and 7, the vibration device 1b comprises a base substrate 2b, a lid 3 joined to the base substrate 2b to form a housing space 4, and a vibration element 30 housed in the housing space 4.

[0029] The base substrate 2b is provided with a recess 5 that is recessed from the top surface on the side opposite to the lid 3, and includes a first mounted electrode 11 and a second mounted electrode 12 provided on the inner bottom surface 6 of the recess 5 and joined to one end 17 of the vibrating element 30, and a pillow portion 13 provided on the inner bottom surface 6 at a position that overlaps with the other end 18 of the vibrating element 30 in a plan view.

[0030] Furthermore, the base substrate 2b is provided with a first protrusion 21 that protrudes from the inner bottom surface 6 at a position that overlaps with the first mounted electrode 11 in a plan view, and a second protrusion 22 that protrudes from the inner bottom surface 6 at a position that overlaps with the second mounted electrode 12 in a plan view. By providing the first protrusion 21 and the second protrusion 22 on the lower surfaces of the first mounted electrode 11 and the second mounted electrode 12, it is possible to prevent the joining member 40 from spreading towards the excitation electrode 32 when the vibration element 30 is mounted.

[0031] This configuration prevents the joining member 40 from spreading towards the excitation electrode 32, and also provides the same effects as in the first embodiment. [Explanation of Symbols]

[0032] 1, 1a, 1b... Vibration device, 2... Base substrate, 3... Cover, 4... Housing space, 5... Recess, 6... Inner bottom surface, 7... Joining member, 11... First mounted electrode, 12... Second mounted electrode, 13... Pillow section, 14... Thick section, 15... Inclined section, 16... Curved surface, 17... One end, 18... Other end, 20... External terminal, 21... First protrusion, 22... Second protrusion, 30... Vibration element, 31... Vibration substrate, 32... Excitation electrode, 33... Lead electrode, 34... Pad electrode, 35... Side electrode, 40... Joining member, L1, L2... Length.

Claims

1. A vibration device comprising an integrally formed base substrate, a lid joined to the base substrate to form a housing space, and a vibration element housed in the housing space, The base substrate is A first mounted electrode and a second mounted electrode are provided on the inner bottom surface and are joined to one end of the vibrating element, The inner bottom surface includes a pillow portion provided at a position that overlaps with the other end of the vibrating element in a plan view, When the direction from the other end of the vibrating element toward the one end is defined as the first direction, The aforementioned pillow portion is The thickened portion protruding from the inner bottom surface, Including an inclined portion that extends from the thickened portion toward the first direction and connects the thickened portion and the inner bottom surface, Vibration device.

2. Let L1 be the length of the first mounted electrode and the second mounted electrode along the first direction. When the length of the pillow portion along the first direction is L2, L1 < L2, The vibration device according to claim 1.

3. The thickened portion and the inclined portion are connected by a curved surface. The vibration device according to claim 1.

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