JP6179838B2 - Quartz crystal resonator and crystal oscillation device - Google Patents

Description

  The present invention relates to a crystal resonator and a crystal resonator device.

  As a piezoelectric vibration element used for an oscillation device, a bandpass filter, and the like, a quartz crystal vibrator having a thickness shear vibration as a main vibration is widely used. As such a quartz crystal resonator, it is known that a plurality of grooves are formed between an excitation electrode and an end portion in the propagation direction where thickness shear vibration propagates in order to improve the confinement of vibration energy. (See Patent Document 1). According to this, it is possible to perform stable processing in that the processing accuracy is high and the yield is expected to be improved as compared with the case of chamfering the quartz crystal substrate by barrel polishing or the like.

  However, according to the configuration described in Patent Document 1, the lead electrode connected to the excitation electrode of the crystal resonator must be formed so as to intersect with the plurality of grooves. There was a possibility of disconnection. Therefore, it may be difficult to maintain stable quality from the viewpoint of electrical connection reliability.

JP 2011-97623 A

  The present invention has been made in view of such circumstances, and an object thereof is to improve the confinement property of vibration energy while maintaining stable quality.

  A crystal resonator according to one aspect of the present invention is a crystal resonator having a thickness-shear vibration as a main vibration, and has a longitudinal direction and a lateral direction, and is a first end that is one end in the longitudinal direction. And an AT-cut quartz crystal substrate, and an excitation electrode provided on a second surface opposite to the first surface of the AT-cut quartz crystal substrate. In the AT-cut quartz substrate, a plurality of openings are formed in the longitudinal direction between at least one of the first end and the second end and the excitation electrode, and the opening area of the plurality of openings is: It increases from the excitation electrode toward the end in the longitudinal direction.

  According to the above configuration, since the opening areas of the plurality of openings are increased from the excitation electrode toward the end in the longitudinal direction, the thickness at the end in the longitudinal direction is larger than that at the center of the quartz substrate. The same effect as that of the small configuration can be obtained, and leakage of vibration energy in the thickness shear vibration mode can be reduced. Therefore, it is possible to improve the confinement property of vibration energy while maintaining stable quality.

  In the crystal resonator, the plurality of openings may be formed both between the first end and the excitation electrode and between the second end and the excitation electrode.

  The crystal resonator further includes an extension electrode that is electrically connected to the excitation electrode and extends toward the second end portion in the longitudinal direction of the AT-cut crystal substrate, and the plurality of openings have a first end. It may be formed between the portion and the excitation electrode.

  According to this, it is possible to prevent disconnection of each electrode due to the recess.

  In the crystal resonator, the numerical apertures of the plurality of openings may increase from the excitation electrode toward the end in the longitudinal direction.

  In the above-described crystal resonator, the opening diameter of each of the plurality of openings may increase from the excitation electrode toward the end in the longitudinal direction.

  In the crystal resonator, the plurality of openings may be concave portions.

  According to this, it can prevent that the mechanical strength of a quartz substrate falls compared with a through-hole.

  In the crystal unit, the plurality of recesses may be formed on the first surface and the second surface of the AT-cut crystal substrate.

  According to this, it is possible to further improve the confinement property of vibration energy.

  In the crystal resonator, any one of the recesses formed on the first surface of the AT-cut crystal substrate may overlap with each of the other plurality of recesses formed on the second surface of the AT-cut crystal substrate. It may be arranged so that there is no.

  According to this, it is possible to prevent the mechanical strength of the quartz substrate from being lowered.

  In the crystal resonator, each of the plurality of openings may be a through hole that penetrates the first surface and the second surface of the AT-cut crystal substrate.

  According to this, the opening can be formed more easily.

  In the crystal resonator, the plurality of openings may be formed by etching.

  A quartz-crystal vibrating device according to one aspect of the present invention includes a base member, a lid member connected to the base member so as to form a sealed internal space, and the above-described crystal resonator housed in the internal space.

  According to the above configuration, since the crystal resonator including the configuration of the crystal substrate is provided, it is possible to improve the confinement property of vibration energy while maintaining stable quality.

  According to the present invention, it is possible to improve the confinement property of vibration energy while maintaining stable quality.

FIG. 1 is a plan view for explaining the crystal resonator according to this embodiment. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a plan view for explaining a crystal resonator according to a first modification of the present embodiment. FIG. 4 is a plan view for explaining a crystal resonator according to a second modification of the present embodiment. FIG. 5 is a cross-sectional view for explaining a crystal resonator according to a third modification of the present embodiment. FIG. 6 is a cross-sectional view for explaining a crystal resonator according to a fourth modification of the present embodiment. FIG. 7 is a plan view for explaining the crystal vibrating device according to the present embodiment. 8 is a cross-sectional view taken along line VIII-VIII in FIG.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar components are denoted by the same or similar reference numerals. The drawings are exemplary, the dimensions and shapes of each part are schematic, and the technical scope of the present invention should not be construed as being limited to the embodiments.

  FIG. 1 is a plan view of a crystal resonator according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

  The crystal resonator 1 according to this embodiment includes a crystal substrate 10 and a pair of first and second excitation electrodes 20 and 30 formed on the crystal substrate 10.

  The quartz substrate 10 is made of, for example, quartz formed by AT cut. A quartz resonator using an AT-cut quartz substrate has extremely high frequency stability over a wide temperature range, is excellent in aging characteristics, and can be manufactured at low cost. In addition, an AT-cut quartz resonator is often used as a main vibration in a thickness shear vibration mode (Thickness Shear Mode). In the example shown in FIGS. 1 and 2, the quartz substrate 10 has a substantially rectangular outer shape having a longitudinal direction parallel to the X direction and a short direction parallel to the Y direction, and the Z plane is based on the XY plane. It has a shape that is substantially symmetrical in the direction. The quartz substrate 10 has a first surface 12 and a second surface 14 opposite to the first surface 12.

  A first excitation electrode 20 is formed on the first surface 12 of the quartz substrate 10, while a second excitation electrode 30 is formed on the second surface 14 of the quartz substrate 10. The first and second excitation electrodes 20 and 30 are arranged as a pair of electrodes so as to substantially overlap each other in the XY plan view. An extension electrode 22 electrically connected to the first excitation electrode 20 is formed on the first surface 12 of the quartz substrate 10. The extension electrode 22 is a second end of the first end portion 16 (end portion on the X-axis positive direction side) and the second end portion 18 (end portion on the X-axis negative direction side) in the longitudinal direction of the quartz crystal substrate 10. It extends toward the portion 18, passes through the second end portion 18 of the quartz substrate 10, and is electrically connected to the connection electrode 24 formed on the second surface 14. On the other hand, an extension electrode 32 that is electrically connected to the second excitation electrode 30 is formed on the second surface 14 of the quartz substrate 10. The extension electrode 32 extends toward the second end portion 18 in the longitudinal direction of the quartz crystal substrate 10 and is electrically connected to the connection electrode 34 formed on the second surface 14. In this way, the connection electrodes 24 and 34 electrically connected to the first and second excitation electrodes 20 and 30 are on the second end 18 side in the longitudinal direction on the second surface 14 of the quartz substrate 10 (that is, the short side). It is arranged on the side. In addition, arrangement | positioning, such as these extended electrodes and a connection electrode, and a routing shape are not limited to the above, You can design freely freely.

  Each of the electrodes including the first and second excitation electrodes 20 and 30 may be formed, for example, by forming a base with a chromium (Cr) layer and forming a gold (Au) layer on the surface of the chromium layer. It is not limited.

  A plurality of recesses 40 are formed in the first surface 12 of the quartz substrate 10 as one mode of the opening. As shown in FIG. 1, the plurality of concave portions 40 are formed side by side in the longitudinal direction between the first end portion 16 in the longitudinal direction of the quartz substrate 10 and the first excitation electrode 20. As shown in FIG. 1, the plurality of recesses 40 may be arranged in a plurality of stages (three stages in FIG. 1) in the longitudinal direction, or may be randomly arranged in the longitudinal direction. The opening area of the plurality of recesses 40 (that is, the total area surrounded by the outer edge of the opening in the XY plan view) increases from the first excitation electrode 20 toward the first end portion 16. In this case, the opening area of the plurality of recesses 40 is not limited to a configuration that is continuously increased along the longitudinal direction, and may be a configuration that increases as a whole in the longitudinal direction. For example, when the space between the first end portion 16 and the first excitation electrode 20 is divided into a plurality of regions (for example, two regions) with the same area in the longitudinal direction, one region on the first end portion 16 side The opening area (that is, the density of the opening) may be larger than the opening area (that is, the density of the opening) of the other region on the first excitation electrode 20 side.

  As shown in FIG. 1, the numerical apertures of the plurality of recesses 40 may increase from the first excitation electrode 20 toward the first end portion 16. The opening diameters of the recesses 40 may be approximately the same size or different sizes.

  Further, the planar shape (the shape in the XY plan view) of the opening of the concave portion 40 may be a circular shape as shown in FIG. Moreover, the sectional shape of the opening of the recess 40 (the shape in the XZ sectional view) may be formed with a tapered inclined surface (curved surface or flat surface) as shown in FIG. As shown, the bottom of the recess 40 may be a portion where the inclined surfaces intersect.

  Such a plurality of recesses 40 can be formed by lithography and etching, for example. For example, a resist layer is formed on a quartz substrate, a plurality of openings are formed in the resist layer by performing exposure and development, and a plurality of regions are etched by etching a plurality of regions of the quartz substrate exposed by the plurality of openings. The recess 40 can be formed. Etching proceeds in the thickness direction (that is, the depth direction) of the quartz substrate so as to form an inclined surface inward from the outer periphery of the recess 40, and finally the position where the inclined surfaces from the outer periphery of the recess 40 intersect. Etching is finished. Therefore, the depth and the inclination angle of the recess 40 depend on the etching time, the opening diameter of the recess 40, and the like.

  The shape and formation method of the recess 40 are not limited to the above. For example, the recess 40 may have a curved inner surface or a shape having a bottom surface and a side wall surface rising vertically from the bottom surface. Good. Or a cone shape may be sufficient and a truncated cone shape may be sufficient. Further, the method of forming the recess 40 is not limited to lithography and etching, and may be formed using other physical and chemical methods.

  In the example illustrated in FIG. 1, when the extension electrode 22 and the connection electrode 24 that are electrically connected to the first excitation electrode 20 are arranged on the second end 18 side in the longitudinal direction of the quartz substrate 10, a plurality of extension electrodes 22 and connection electrodes 24 are provided. The recess 40 is formed on the first end 16 side in the longitudinal direction of the quartz substrate 10. That is, the plurality of recesses 40 are formed avoiding the arrangement of the extension electrode 22 and the connection electrode 24. Therefore, it is possible to prevent the electrode from being disconnected due to the recess 40.

  In the present embodiment, as shown in FIG. 2, the second surface 14 of the quartz substrate 10 is also formed with a plurality of recesses 42 as one aspect of the opening. The plurality of recesses 42 are formed side by side in the longitudinal direction between the first end 16 in the longitudinal direction of the quartz substrate 10 and the second excitation electrode 30. That is, the range in which the plurality of recesses 42 are formed substantially overlaps the range in which the recesses 40 are formed. Then, similarly to the content described for the recess 40, the opening areas of the plurality of recesses 42 increase from the first excitation electrode 20 toward the first end portion 16. The other configurations of the recess 42 are the same as those described for the recess 40 described above.

  As shown in FIG. 2, the plurality of recesses 40, 42 includes a plurality of recesses formed on the second surface 14 of the crystal substrate 10, any one of the recesses 40 formed on the first surface 12 of the crystal substrate 10. Each of 42 is arranged so as not to overlap. In other words, the center of any one of the recesses 40 is arranged so as not to overlap with the center of each of the plurality of recesses 42. Any one of the recesses 40 may not overlap all of the plurality of recesses 42, or may be arranged so as to overlap only a part of any one of the recesses 42. As described above, the recesses 40 and 42 are arranged so as to be offset from each other, and even if a plurality of recesses are formed from both sides of the quartz substrate 10, the mechanical strength of the quartz substrate 10 is prevented from being lowered. Can do.

  According to the crystal unit 1 according to the present embodiment, the opening areas of the plurality of recesses 40 and 42 are directed from the first and second excitation electrodes 20 and 30 toward the end in the longitudinal direction (for example, the first end 16). It is possible to have the same effect as the structure in which the thickness of the end portion in the longitudinal direction is smaller than the central portion of the quartz substrate 10 which is larger than the center portion, and the leakage of vibration energy in the thickness shear vibration mode is reduced. be able to. Therefore, it is possible to improve the confinement property of vibration energy while maintaining stable quality.

  Next, a crystal resonator according to a modification of the present embodiment will be described with reference to FIGS. In the following modification, points different from the above contents will be described.

  FIG. 3 is a plan view showing a crystal resonator 2 according to a first modification of the present embodiment. As shown in this modification, a plurality of recesses may be formed on one end side in the longitudinal direction on the first surface, and may be formed on the other end side in the longitudinal direction on the second surface.

  As shown in FIG. 3, the crystal resonator 2 has a crystal substrate 11, and a plurality of recesses 40 are formed on the first surface 12 of the crystal substrate 11 between the first end portion 16 and the first excitation electrode 20. In the formed second surface 14 of the quartz substrate 11, a plurality of recesses 44 are formed between the second end 18 and the second excitation electrode 30. In this case, it is preferable that the plurality of recesses 40 and 44 be formed avoiding the arrangement of the extension electrode and the connection electrode. In addition, the content of the recessed part demonstrated about the said embodiment is applicable to the other structure of the recessed parts 40 and 44. FIG.

  In the example shown in FIG. 3, the plurality of concave portions 44 are formed on the second end 18 side, which is the connection electrode 24 side, on the second surface 14, but the present invention is not limited to this. A plurality of recesses 44 may be formed on the first end 16 side in the surface 14 (in this case, a plurality of recesses 40 are formed on the second end 18 side in the first surface 12). Thereby, a plurality of recesses can be freely formed on the second surface 14 without being obstructed by the arrangement of the connection electrodes.

  FIG. 4 is a plan view showing a crystal resonator 3 according to a second modification of the present embodiment. As shown in this modification, a plurality of recesses may be formed on both end portions of the quartz substrate.

  As shown in FIG. 4, the crystal resonator 3 has a crystal substrate 50, and the first surface 12 of the crystal substrate 50 is arranged in the longitudinal direction between the first end portion 16 and the first excitation electrode 20. A plurality of recesses 52 are formed, and a plurality of recesses 54 are formed between the second end portion 18 and the first excitation electrode 20 in the longitudinal direction. The opening area of the plurality of recesses 54 increases from the first excitation electrode 20 toward the second end 18, and more specifically, the numerical aperture (that is, the number of recesses) increases. The plurality of recesses 54 are preferably formed in a region that avoids the extended electrode 22. Thereby, it is possible to prevent the electrode from being disconnected due to the recess 54. The recesses 52 and 54 may also be formed on the second surface 14 of the quartz substrate 50. In addition, the content of the recessed part demonstrated about the said embodiment is applicable to the other structure of the recessed parts 52 and 54. FIG. According to this modification, since the plurality of recesses 52 and 54 are formed on both ends of the quartz substrate 50, it is possible to further improve the energy vibration confinement.

  FIG. 5 is a plan view showing a crystal resonator 5 according to a third modification of the present embodiment. As shown in this modification, the plurality of recesses may have larger opening diameters on the end portion side in the longitudinal direction than on the excitation electrode side.

  As shown in FIG. 5, the crystal unit 5 includes a crystal substrate 60, and is arranged on the first surface 12 of the crystal substrate 60 in the longitudinal direction between the first end portion 16 and the first excitation electrode 20. A plurality of recesses 62, 64, 66 are formed. Specifically, the concave portion 62, the concave portion 64, and the concave portion 66 are arranged in this order along the positive direction of the X axis. The concave portion 64 has a larger opening diameter than the concave portion 62, and the concave portion 66 has a larger opening diameter than the concave portion 64. The opening diameter is larger. In addition, the several recessed part from which these opening diameters differ may be formed in the 2nd end part 18 side similarly to the content already demonstrated, or may be formed also in the 2nd surface 14. FIG. Further, in combination with the configuration of the above embodiment, the opening area of the plurality of recesses may be increased in the longitudinal direction by combining the numerical aperture and the opening diameter.

  FIG. 6 is a cross-sectional view showing a crystal resonator 7 according to a fourth modification of the present embodiment. As shown in this modification, the plurality of openings may be through holes.

  As shown in FIG. 6, the crystal resonator 7 has a crystal substrate 70, and a plurality of through holes 72 that penetrate the first surface 12 and the second surface 14 are formed in the crystal substrate 70. As shown in FIG. 6, the plurality of through holes 72 are formed side by side in the longitudinal direction between the first end portion 16 and the first excitation electrode 20 (and the second excitation electrode 30). Alternatively, the plurality of through holes may be formed between the second end portion 16 and the first excitation electrode 20 (and the second excitation electrode 30). When the through hole 72 is formed on the second end portion 16 side, the through hole 72 is preferably formed in a region that avoids the extended electrodes 22 and 32 and the connection electrodes 24 and 34.

  The planar shape (the shape in the XY plan view) of the opening of the through hole 72 may be a circular shape, a rectangular shape, an elliptical shape, or the like. Further, the cross-sectional shape of the through-hole 72 (XZ cross-sectional view shape) may be formed with a tapered inclined surface (curved surface or flat surface) as shown in FIG. For example, when the through hole 72 is formed by etching, the opening diameter may be gradually reduced from the first surface 12 or the second surface 14 toward the center of the crystal substrate 60.

  Next, with reference to FIG.7 and FIG.8, the crystal vibrating device which concerns on this embodiment is demonstrated. Here, FIG. 7 shows a plan view of the crystal resonator device according to the present embodiment, and FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. In FIG. 7, the lid member is omitted.

  As shown in FIG. 7, the crystal resonator device 100 according to this embodiment includes the crystal resonator device 1 and a package member 110 in which the crystal resonator device 1 is accommodated.

  The package member 110 includes a base member 120 and a lid member 130. The crystal resonator 1 is accommodated in a sealed internal space (cavity) 112 formed by connecting a base member 120 and a lid member 130. Specifically, the crystal unit 1 is supported by the package member 110 (base member 120) so that one end where the connection electrodes 24 and 34 are disposed is a fixed end, and the other end of the crystal unit 1 is free. It is housed to be at the end. The base member 120 may be formed of an insulating ceramic such as alumina, or may be formed of another insulating material such as a synthetic resin. The lid member 130 may be formed of, for example, a metal, an insulating material such as insulating ceramics or synthetic resin, or a composite material thereof.

  A plurality of electrodes 122 and 124 are formed on the upper surface of the base member 120 on which the crystal resonator 1 is mounted. The plurality of electrodes 122 and 124 are electrically connected to the connection electrodes 24 and 34 of the crystal resonator 1 via the conductive adhesive 116, respectively. The electrode 122 of the base member 120 is electrically connected to the external electrode 123 provided on the back surface of the corner portion of the base member 120 through the extension electrode 122a, while the electrode 124 of the base member 120 is the extension electrode. It is electrically connected to the external electrode 125 provided on the back surface of the other corner portion of the base member 120 via 124a. The external electrodes 123 and 125 may be provided at positions facing each other in the XY plan view of the crystal unit 1 (for example, positions on a diagonal line of a substantially rectangular outer shape as shown in FIG. 6). Further, in the example shown in FIG. 6, the external electrodes 126 and 128 may be formed in corner portions other than the corner portion where the external electrodes 123 and 125 are provided. These external electrodes 126 and 128 may be grounded or may be dummy electrodes that are not electrically connected.

  As shown in FIG. 7, the lid member 130 has an opening for forming the internal space 112. The lid member 130 is, for example, a cap, and the open end portion of the lid member 130 is bonded to the outer peripheral end portion of the base member 120 by the insulating adhesive 114, so that the sealed internal space 112 can be formed. Good. Or the connection aspect of the base member 120 and the lid member 130 is not restricted to the thing by resin materials, such as an adhesive agent, For example, you may apply welding sealing and glass sealing.

  In the example shown in FIG. 7, the lid member 130 has a shape having an opening for forming the internal space 112. However, as another example, the base member 120 in which the external electrode is formed is replaced with the internal space 112. You may form in the shape which has the opening for forming.

  In such a crystal oscillating device 100, by applying an AC voltage between the pair of first and second excitation electrodes 20, 30 in the crystal resonator 1 via the external terminals 123, 125, the thickness shear mode is applied. Thus, the quartz resonator element 10 vibrates, and the resonance characteristics associated with the vibration are obtained.

  According to the crystal oscillating device 100 according to the present embodiment, since the crystal resonator 1 described above is provided, it is possible to provide a crystal oscillating device having high vibration energy confinement properties while maintaining stable quality.

  The present invention is not limited to the above-described embodiment, and can be variously modified and applied. The contents described in each of the above embodiments (or modifications) can be applied in appropriate combination with the contents described in the other embodiments.

  In the above description, the embodiment in which the opening of the present invention is formed on the assumption that the quartz substrate has a substantially rectangular parallelepiped shape has been described. However, the present invention is not limited to this. It does not exclude the aspect of forming the opening of the present invention on the premise of a shape in which the thickness is gradually reduced from the central portion toward the end portion, such as a bell structure or a convex structure.

  Each embodiment described above is for facilitating the understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed / improved without departing from the spirit thereof, and the present invention includes equivalents thereof. In other words, those obtained by appropriately modifying the design of each embodiment by those skilled in the art are also included in the scope of the present invention as long as they include the features of the present invention. For example, each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate. In addition, each element included in each embodiment can be combined as much as technically possible, and combinations thereof are included in the scope of the present invention as long as they include the features of the present invention.

DESCRIPTION OF SYMBOLS 1 Crystal resonator 10 Crystal substrate 11 Crystal substrate 12 1st surface 14 2nd surface 16 1st edge part 18 2nd edge part 20 1st excitation electrode 22 Extension electrode 30 2nd excitation electrode 32 Extension electrode 40 Recessed part 42 Recessed part 44 recess 50 crystal substrate 52 recess 54 recess 60 crystal substrate 62 recess 70 crystal substrate 72 through hole 100 crystal oscillation device 112 internal space 120 base member 130 lid member

Claims (10)

It is a crystal unit whose thickness vibration is the main vibration.
An AT-cut quartz crystal substrate having a longitudinal direction and a transverse direction, and having a first end that is one end in the longitudinal direction and a second end that is the other end;
An excitation electrode provided on a first surface of the AT-cut quartz substrate and a second surface opposite to the first surface;
An extension electrode electrically connected to the excitation electrode;
A connection electrode electrically connected to the excitation electrode and the extension electrode;
With
In the AT-cut quartz substrate, a plurality of openings are arranged in the longitudinal direction between at least one of the first end and the second end and the excitation electrode, and the extension electrode and the connection electrode Formed avoiding the placement of
The opening area of the plurality of openings is increased from the excitation electrode toward the end in the longitudinal direction,
The quartz resonator in which the numerical apertures of the plurality of openings increase from the excitation electrode toward the end in the longitudinal direction.   2. The crystal resonator according to claim 1, wherein the plurality of openings are formed both between the first end and the excitation electrode and between the second end and the excitation electrode. . The extension electrode extends toward the second end in the longitudinal direction of the AT-cut quartz crystal substrate ,
The quartz resonator according to claim 1, wherein the plurality of openings are formed between the first end and the excitation electrode.   4. The crystal resonator according to claim 1, wherein an opening diameter of each of the plurality of openings is increased from the excitation electrode toward an end in the longitudinal direction. 5.   5. The crystal resonator according to claim 1, wherein the plurality of openings are concave portions.   The crystal unit according to claim 5, wherein the plurality of recesses are formed on the first surface and the second surface of the AT-cut crystal substrate.   Any one of the recesses formed on the first surface of the AT-cut quartz substrate does not overlap with each of the other plurality of recesses formed on the second surface of the AT-cut crystal substrate. The crystal resonator according to claim 6, wherein   5. The crystal resonator according to claim 1, wherein each of the plurality of openings is a through-hole penetrating the first surface and the second surface of the AT-cut crystal substrate.   The quartz resonator according to claim 1, wherein the plurality of openings are formed by etching. A base member;
A lid member connected to the base member to form a sealed interior space;
The crystal resonator according to any one of claims 1 to 9, which is accommodated in the internal space;
Quartz vibrating device comprising.

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