Resonator

Abstract

PURPOSE: To provide a resonator which can efficiently suppress sub waves.SOLUTION: The resonator includes a vibrator, a first electrode, and a second electrode. The vibrator has a first surface and a second surface facing each other. The first electrode is arranged on the first surface and the second electrode is arranged on the second surface. At least one of the first electrode and the second electrode has a plurality of openings. The openings are distributed in pairs. Each pair of openings is distributed symmetrically to the geometric center of the corresponding electrode and each opening is not in contact with the edge of the corresponding electrode.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] The present invention relates to electronic components, and more particularly to resonators.

Background Art

[0002] A resonator is an electronic component that utilizes the piezoelectric properties of a material and the natural resonance frequency of the material. A crystal is a common piezoelectric material used in resonators. In a well-known resonator, electrodes are provided on both sides of a piezoelectric material. When a voltage difference is applied between these two electrodes, the piezoelectric material deforms due to the inverse piezoelectric effect. Subsequently, when this voltage difference is removed, the piezoelectric material continues to vibrate, and due to the piezoelectric effect, a change in voltage associated with the vibration occurs between these two electrodes, so that a voltage signal can be output from these two electrodes.

[0003] Due to physical limitations, frequencies in the vicinity of the main wave of vibration of a piezoelectric material (e.g., the thickness shear vibration mode) often involve secondary waves such as bending vibration and surface shear vibration, that is, unwanted modes. If the difference between the frequency of the secondary wave and the frequency of the main wave is too small, the secondary wave is likely to combine with the main wave, affecting product characteristics. In particular, in applications with a wide operating temperature range such as in-vehicle use and miniaturized in-vehicle use, the secondary wave becomes an even more troublesome problem.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides a resonator capable of effectively suppressing secondary waves.

Means for Solving the Problems

[0005] One embodiment of the present invention provides a resonator including a diaphragm, a first electrode, and a second electrode. The diaphragm has opposite first and second surfaces, the first electrode is disposed on the first surface, and the second electrode is disposed on the second surface. At least one of the first electrode and the second electrode has a plurality of openings, the openings are distributed in pairs, each pair of openings is symmetrically distributed with respect to the geometric center of the electrode to which it belongs, and all the openings do not contact the edge of the electrode to which they belong.

Effects of the Invention

[0006] In the resonator according to the embodiment of the present invention, at least one of the first electrode and the second electrode has a plurality of openings, the openings are distributed in pairs, each pair of openings is symmetrically distributed with respect to the geometric center of the electrode to which it belongs, and all the openings do not contact the edge of the electrode to which they belong. Therefore, the resonator according to the embodiment of the present invention can effectively suppress spurious waves.

Brief Description of the Drawings

[0007]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 2C

Figure 2D

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 4

Embodiments for Carrying Out the Invention

[0008] FIG. 1A is a schematic cross-sectional view of a resonator according to one embodiment of the present invention, and FIG. 1B is a schematic perspective view of the diaphragm, the first electrode, and the adhesive of FIG. 1A. Here, the cross-sections of the diaphragm, the first electrode, and the second electrode in FIG. 1A are cross-sections taken along line I-I in FIG. 1B. Referring to FIGS. 1A and 1B, the resonator 100 of this embodiment includes a diaphragm 110, a first electrode 120, and a second electrode 130. The diaphragm 110 has opposing first and second surfaces 112 and 114, the first electrode 120 is disposed on the first surface 112, and the second electrode 130 is disposed on the second surface 114. In this embodiment, the material of the diaphragm 110 is a piezoelectric material. For example, the diaphragm 110 is a quartz plate. Also, the first electrode 120 and the second electrode 130 are each one electrode layer.

[0009] The first electrode 120 and the second electrode 130 are suitable for a voltage difference to be applied, and when a voltage difference exists between the first electrode 120 and the second electrode 130, the diaphragm 110 deforms due to the inverse piezoelectric effect. Then, when this voltage difference is removed, the diaphragm 110 continues to vibrate, and due to the piezoelectric effect, a voltage change associated with this vibration occurs between the first electrode 120 and the second electrode 130, so that a voltage signal can be output from the first electrode 120 and the second electrode 130.

[0010] In the resonator 100 of the present embodiment, at least one of the first electrode 120 and the second electrode 130 has a plurality of openings 140 (FIG. 1A shows a case where both the first electrode 120 and the second electrode 130 have a plurality of openings 140 as an example). The openings 140 of the first electrode 120 expose a part of the first surface 112 of the diaphragm 110, and the openings 140 of the second electrode 130 expose the second surface 114 of the diaphragm 110. The openings 140 are distributed in pairs, and each pair of openings 140 is symmetrically distributed with respect to the geometric center C1 of the electrode to which it belongs, and all the openings 140 do not contact the edge of the electrode to which they belong. In the present embodiment, the ratio of the area of the opening 140 to the area of the electrode to which it belongs is less than or equal to 30%. The distance D1 between the geometric center C2 of each opening 140 and the geometric center C1 of the electrode to which it belongs is greater than or equal to the distance I1 between the first electrode 120 and the second electrode 130 (i.e., the thickness of the main vibration region of the diaphragm 110), and the distance D2 between each opening 140 and the edge of the electrode to which it belongs is greater than or equal to the distance I1 between the first electrode 120 and the second electrode 130. Therefore, the resonator 100 of the present embodiment can effectively suppress the sub-wave. When the ratio of the area of the opening 140 to the area of the electrode to which it belongs is less than or equal to 30%, the vibration of the main wave (i.e., the thickness shear vibration mode) can be hardly impaired, and the sub-wave vibration (e.g., unnecessary vibration modes such as bending vibration and surface shear vibration) can be effectively suppressed. Further, since the electrodes of the resonator 100 of the present embodiment have an even number of openings 140 that penetrate the electrodes and are not connected to each other, the sub-wave can be effectively suppressed. Furthermore, when the distance D1 between the geometric center C2 of each opening 140 and the geometric center C1 of the electrode to which it belongs is greater than or equal to the distance I1 between the first electrode 120 and the second electrode 130 (i.e., the thickness of the main vibration region of the diaphragm 110), and the distance D2 between each opening 140 and the edge of the electrode to which it belongs is greater than or equal to the distance I1 between the first electrode 120 and the second electrode 130, the influence received by the main vibration region of the diaphragm 110 from the opening can be reduced, thereby increasing the vibration intensity of the thickness shear vibration mode and effectively suppressing the sub-wave.In one embodiment, the distance D1 between the geometric center C2 of each opening 140 and the geometric center C1 of the corresponding electrode is greater than or equal to 5 times the interval I1 between the first electrode 120 and the second electrode 130 (i.e., the thickness of the main vibration region of the diaphragm 110).

[0011] In this embodiment, the distances D1 from the geometric center C1 of the corresponding electrode to the geometric centers C2 of the two openings 140 in each pair of openings 140 or to the geometric center C2 of all the openings 140 are the same as each other. By doing so, the vibration intensity in the thickness-shear vibration mode can be increased. Also, in this embodiment, the openings 140 are not connected to each other.

[0012] In this embodiment, both the first electrode 120 and the second electrode 130 have openings 140, and the shape and position of the opening 140 of the first electrode 120 respectively correspond to the shape and position of the opening 140 of the second electrode 130. However, in other embodiments, one of the first electrode 120 and the second electrode 130 may have an opening 140, and the other of the first electrode 120 and the second electrode 130 may not have an opening 140.

[0013] In this embodiment, the resonator 100 further includes a base 150 and at least one adhesive 160 (FIG. 1B shows two adhesives 160 as an example). The diaphragm 110 is disposed on the base 150 and is fixed on the base 150 by, for example, the adhesive 160. In this embodiment, the base 150 has a concave groove 152, and the diaphragm 110 is disposed in the concave groove 152. Further, in this embodiment, the resonator 100 further includes a cover 170 disposed on the base 150 and covering the diaphragm 110. In this embodiment, the cover 170 can be disposed on the base 150 via a seal ring 180.

[0014] In this embodiment, the resonator 100 further includes a plurality of contact pads 190 disposed below the base 150. The contact pads 190 can be electrically connected to the first electrode 120 and the second electrode 130 via a conductive adhesive 160 and a conductive trace 195, respectively. In this way, an external voltage can be applied onto the contact pads 190, and the change in the output voltage of the contact pads 190 can be sensed.

[0015] In this embodiment, since each opening 140 has at least one straight long side S1 (FIG. 1B shows an example of one straight long side S1), the vibration boundary is smoothed, and the vibration intensity of the thickness-shear vibration mode can be increased. In this embodiment, the openings 140 are symmetrically distributed with the geometric center C1 of the corresponding electrode as the symmetry point. Among any two symmetrically distributed openings 140, at least two straight long sides S1 (FIG. 1B shows an example of two linear and opposite long sides S1) are parallel to each other. Moreover, since any two symmetrically distributed openings 140 are relative to their straight long sides S1, such a design can further suppress the secondary wave. In this embodiment, the edge of each opening 140 and the edge of the corresponding electrode do not contact each other. That is, since the edge of the opening 140 and the edge of the corresponding electrode have a distance D2, such a design can reduce the loss of vibration energy and maintain the vibration intensity of the thickness-shear vibration mode.

[0016] In this embodiment, any two symmetrically distributed openings 140 are respectively located near two opposite sides of the corresponding electrode. FIG. 1B shows an example in which four openings 140 are respectively located near the four sides of the corresponding electrode. Further, in this embodiment, each opening 140 is a quadrilateral opening. FIG. 1B shows a trapezoidal opening as an example, but in other embodiments, it may be rectangular or of other shapes.

[0017] Figs. 2A to 2D are top views of the diaphragm and the first electrode according to another four embodiments of the present invention. First, referring to Figs. 2A and 2B, in these two embodiments, the openings 140a and 140b are rectangular, but the openings 140a and 140b are arranged on two separate opposite sides of the electrode to which they belong (the figure takes the first electrode 120 as an example). Next, referring to Fig. 2C, in this embodiment, any two symmetric openings 140c are respectively located near two opposite corners of the electrode to which they belong (the figure takes the first electrode 120 as an example), and Fig. 2C takes the case where the four openings 140c are respectively located near the four corners of the electrode to which they belong as an example. Also, when viewed from another perspective, referring to Fig. 2A, each opening 140a has two linear long sides S1, and the two ends of the two linear long sides S1 are respectively connected by a straight side S2. Further, referring to Fig. 2D, in this embodiment, each opening 140i has two linear long sides S1, and the two ends of the two linear long sides S1 are respectively connected by a curved side S3.

[0018] Figs. 3A to 3E are top views of the diaphragm and the first electrode according to another five embodiments of the present invention. Referring to Figs. 3A to 3D, in this embodiment, the other side opposite to the linear long side S1 of each of the openings 140d, 140e, 140f, 140g has at least one rounded corner R1 (the figure takes two rounded corners R1 as an example). Here, in Fig. 3A, the four openings 140d are respectively located near the four sides of the electrode to which they belong (for example, the first electrode 120). In Figs. 3B and 3C, the openings 140e and 140f are arranged on two separate opposite sides of the electrode to which they belong (the figure takes the first electrode 120 as an example), and in Fig. 3D, the four openings 140g are respectively located near the four corners of the electrode to which they belong. Further, referring to Fig. 3E, in this embodiment, each opening 140j has one linear long side S1 and one curved side S4, and the linear long side S1 and the curved side S4 are respectively located on two opposite sides of the opening 140j.

[0019] FIG. 4 is a schematic three-dimensional view of a diaphragm, a first electrode, and an adhesive according to another embodiment of the present invention. Referring to FIG. 4, the resonator of this embodiment is similar to the resonator 100 in FIGS. 1A and 1B. The difference between the two is that both the upper and lower sides of the diaphragm 110h of the resonator of this embodiment each have one concave groove 111 (FIG. 4 takes the concave groove 111 located on the upper side as an example), and the first electrode 120 and the second electrode (located on the lower side blocked by the diaphragm 110h) are respectively located in the two concave grooves. Since the present invention does not limit the shape of the diaphragm, the diaphragm may be a flat plate as shown in FIG. 1B, or a diaphragm 110h as shown in FIG. 4 or a diaphragm of other shapes.

[0020] As described above, in the resonator according to the embodiment of the present invention, at least one of the first electrode and the second electrode has a plurality of openings. The openings are distributed in pairs, and each pair of openings is symmetrically distributed with respect to the geometric center of the electrode to which it belongs, and all the openings do not contact the edge of the electrode to which they belong. Therefore, the resonator according to the embodiment of the present invention can effectively suppress spurious waves.

Industrial Applicability

[0021] The resonator of the present invention can be applied to fields such as electronic components and electronic devices.

Explanation of Reference Numerals

[0022] 100 Resonator 110, 110h Diaphragm 111 Concave Groove 112 First Surface 114 Second Surface 120 First Electrode 130 Second Electrode 140, 140a, 140b, 140c, 140d, 140e, 140f, 140g, 140i, 140j Opening 150 Base 152 Concave Groove 160 Adhesive 170 Cover 180 Seal Ring 190 Contact Pad 195 Conductive Trace C1, C2 Geometric Center D1, D2 Distance I1 Interval R1 Rounded Corner S1 Straight Long Side S2 Straight Side S3, S4 Curved Sides

Claims

1. a diaphragm having opposing first and second surfaces; a first electrode disposed on the first surface; a second electrode disposed on the second surface; at least one of the first and second electrodes has a plurality of apertures, the apertures being distributed in pairs, the apertures of each pair being distributed symmetrically with respect to the geometric center of the associated electrode, and none of the apertures being in contact with an edge of the associated electrode.

2. 2. The resonator according to claim 1, wherein the distances from the geometric centres of each of the two openings in each pair of openings or from the geometric centres of all said openings to the geometric centre of the associated electrode are the same.

3. The resonator of claim 1 , wherein the apertures are not interconnected.

4. 2. The resonator according to claim 1, wherein the distance between the geometric center of each opening and the geometric center of the associated electrode is greater than or equal to the spacing between the first electrode and the second electrode.

5. The resonator of claim 1 , wherein each opening has at least one straight major side.

6. 6. The resonator according to claim 5, wherein each opening has two straight long sides, and two ends of the two straight long sides are connected by one curved side or one straight side, respectively.

7. 6. The resonator of claim 5, wherein each aperture has one straight long side and one curved side, the straight long side and the curved side being located on two opposite sides of the aperture, respectively.

8. 2. The resonator according to claim 1, wherein the percentage of the area of ​​the opening to the area of ​​the electrode to which it belongs is less than or equal to 30%.

9. 6. The resonator according to claim 5, wherein the apertures are distributed symmetrically with respect to the geometric center of the electrode to which they belong, and at least two straight long sides of any two symmetrical apertures are parallel to each other, and any two symmetrical apertures are relative to the straight long sides.

10. 10. The resonator according to claim 9, wherein any two symmetrical openings are located near two opposite sides of the electrode to which they belong.

11. 10. The resonator according to claim 9, wherein any two symmetrical openings are located near two opposite corners of the electrode to which they belong.

12. 6. The resonator according to claim 5, wherein another side of each opening opposite said linear longer side has at least one rounded corner.

13. 6. The resonator of claim 5, wherein each aperture is a quadrilateral aperture.

14. 2. The resonator according to claim 1, wherein the distance between each opening and the geometric center of the associated electrode is greater than or equal to five times the spacing between the first and second electrodes.

15. The resonator according to claim 1 , wherein the first electrode and the second electrode both have the opening, and the shape and position of the opening in the first electrode correspond to the shape and position of the opening in the second electrode, respectively.

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