Crystal resonator element, and crystal resonator having the same

Abstract

The present invention relates to a crystal vibrating element and a crystal vibrator having the crystal vibrating element. The crystal vibrating element comprises: a crystal plate (11) having a predetermined crystal orientation and having a first direction and a second direction when viewed from above; and excitation electrodes (14a, 14b) respectively arranged on the front and back sides of the crystal plate (11) so as to excite thickness shear vibration of the crystal plate (11) when an alternating electric field is applied, wherein a vibration distribution in the crystal plate (11) with thickness shear vibration as a main vibration comprises a vibration region (40) extending in a band shape in the second direction of the crystal plate (11) and non-vibration regions (50) adjacent to both sides of the vibration region (40) in the first direction of the crystal plate (11).

Description

[0001] The present application is a divisional application of the application with application number 201680058556.3, application date October 7, 2016, and invention name “Crystal Vibration Element, and Crystal Vibrator Having the Crystal Vibration Element”. Technical Field

[0002] The present invention relates to a crystal vibration element and a crystal oscillator. Background Art

[0003] As a signal source of a reference signal used in an oscillator, a bandpass filter, etc., a crystal oscillator that mainly vibrates by thickness shear vibration is widely used.

[0004] For example, Patent Document 1 discloses a piezoelectric vibration element that is held inside a sealed space of a holder and has an excitation electrode disposed near the center of a piezoelectric plate. The vibration distribution of the thickness shear vibration in this piezoelectric vibration element spreads approximately concentrically from the center of the piezoelectric plate to the outside, and the vibration displacement decreases as it moves toward the outside of the piezoelectric plate. Patent Document 2 discloses a structure that suppresses the deterioration of characteristics such as the crystal impedance (Crystal Impedance, hereinafter referred to as "CI") value caused by the vibration of the vibration part being hindered by the outflow of fixing components such as adhesive by making the dimensions of the mesa-type piezoelectric vibration piece satisfy a prescribed relationship. Furthermore, Patent Documents 3 and 4 disclose a structure in which an excitation electrode is formed on the main surface of a crystal piece having an elongated shape until it reaches the edge of the long side of the crystal piece.

[0005] Patent Document 1: Japanese Patent No. 4458203

[0006] Patent Document 2: Japanese Patent Application Publication No. 2013-102472

[0007] Patent Document 3: Japanese Patent Publication No. 56-36814

[0008] Patent Document 4: Japanese Patent Application Publication No. 2001-7677

[0009] However, in the case of a piezoelectric vibration element having a roughly concentric vibration distribution as in Patent Document 1, there is a region adjacent to the roughly concentric outer side of the piezoelectric plate where the displacement caused by the vibration is small or there is no displacement at all, so the drive level dependency (Drive Level Dependence, hereinafter referred to as "DLD") characteristic deteriorates. In addition, since the width of the vibration region is narrower than the width of the crystal piece, the CI value is high, the capacitance ratio γ value becomes large, and good vibration characteristics cannot be obtained.

[0010] Furthermore, in the configurations described in Patent Documents 3 and 4, it may be impossible to sufficiently prevent vibration leakage to the main vibration. Summary of the invention

[0011] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a crystal oscillator capable of obtaining good vibration characteristics.

[0012] A crystal vibrating element according to one embodiment of the present invention comprises: a crystal piece having a prescribed crystal orientation and having a first direction and a second direction when viewed from above; and excitation electrodes, respectively arranged on the surface and back side of the crystal piece so as to excite the crystal piece to undergo thickness shear vibration having a main vibration in the first direction when an alternating electric field is applied, wherein the vibration distribution in the crystal piece having the thickness shear vibration as the main vibration comprises a vibration region extending in a band shape in the second direction of the crystal piece, and non-vibration regions adjacent to both sides of the vibration region in the first direction of the crystal piece.

[0013] A crystal vibrating element according to another embodiment of the present invention comprises: a crystal piece which is cut by AT and has a first direction and a second direction when viewed from above; and an excitation electrode which is arranged opposite to the surface and the back surface of the crystal piece, wherein the vibration distribution of the thickness shear vibration having a main vibration in the first direction excited by the excitation electrode in the crystal piece comprises two amplitude nodes which extend transversely across two sides of the crystal piece opposite to each other in the second direction and are arranged opposite to each other at a distance in the first direction, and an amplitude antinode of the vibration region which is arranged at a position sandwiched by the two nodes.

[0014] A crystal vibrating element according to another embodiment of the present invention comprises: a crystal piece having a prescribed crystal orientation and having a first direction and a second direction when viewed from above; and excitation electrodes, respectively arranged on the surface and back of the crystal piece so as to have a vibration region located in the center of the first direction and vibrating at least by thickness shear vibration, and non-vibrating regions on both sides of the vibration region sandwiched in the first direction, wherein the boundary between the vibration region and the non-vibrating region connects two edges of the crystal piece extending along the first direction and opposite to each other in the second direction, and extends in a wavy manner in the second direction.

[0015] Another embodiment of the present invention involves a crystal vibration element that mainly vibrates by thickness shear vibration, and comprises: a crystal piece having a rectangular main surface on the front and back sides; and rectangular excitation electrodes, respectively formed on each main surface of the crystal piece, and the long edge of the excitation electrode is parallel to the long edge of the corresponding crystal piece. If the distance between the long edge of the excitation electrode and the long edge of the corresponding crystal piece is set to G, and the thickness between each excitation electrode in the crystal piece is set to T, then the relationship is 0<G / T≤0.5.

[0016] According to the present invention, a crystal resonator element and a crystal resonator capable of obtaining good vibration characteristics can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an exploded perspective view of the crystal oscillator according to the first embodiment of the present invention.

[0018] Figure 2 yes Figure 1 Sectional view along line II-II.

[0019] Figure 3 yes Figure 1 A three-dimensional image of the crystal vibrating element in a crystal oscillator.

[0020] Figure 4A Yes means Figure 3 A diagram of the vibration distribution of the thickness shear vibration of a crystal vibration element.

[0021] Figure 4B Yes means Figure 3 A diagram showing simulation results of vibration distribution in a crystal vibration element.

[0022] Figure 4C 1 is a diagram showing simulation results of the X-direction component of the vibration distribution in the crystal resonator element according to the first modification (corresponding to the X-direction component of the crystal orientation).

[0023] Figure 4D It is a diagram showing the simulation results of the Z-direction component (corresponding to the Y′-direction component of the crystal orientation) of the vibration distribution in the crystal resonator element according to the first modification.

[0024] Figure 4E It is a diagram showing the simulation results of the Y-direction component (corresponding to the Z′-direction component of the crystal orientation) of the vibration distribution in the crystal resonator element according to the first modification.

[0025] Figure 5 It is a side view of a crystal resonator element according to a second modification.

[0026] Figure 6 Yes means Figure 5 The crystal resonator element shown is a side view of a vibration state of the crystal resonator element according to the embodiment of the present invention with a wave number n=4 when the crystal resonator element vibrates by thickness shear vibration having a main vibration in the first direction.

[0027] Figure 7 Yes means Figure 5 The crystal resonator element shown is a side view of a vibration state of the crystal resonator element according to the embodiment of the present invention with a wave number n=5 when the crystal resonator element vibrates by thickness shear vibration having a main vibration in the first direction.

[0028] Figure 8 Yes means Figure 5 The crystal resonator element shown is a side view of a vibration state of a crystal resonator element according to a comparative embodiment of the present invention at a wave number n=4.5 when the crystal resonator element vibrates by thickness shear vibration having a main vibration in the first direction.

[0029] Fig.9A It is a diagram showing the simulation results of the X-direction component of the vibration distribution in the crystal resonator element according to the third modification (corresponding to the X-direction component of the crystal orientation).

[0030] Fig. 9B It is a diagram showing the simulation results of the Z-direction component (corresponding to the Y′-direction component of the crystal orientation) of the vibration distribution in the crystal resonator element according to the third modification.

[0031] Fig.10 It is a diagram showing a crystal resonator element according to a fourth modification.

[0032] Fig.11A 1 is a diagram showing simulation results of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification.

[0033] Fig. 11B 1 is a diagram showing simulation results of the vibration distribution on the back side in the thickness direction of the crystal resonator element according to the fourth modification.

[0034] Fig. 11C It is a diagram showing the simulation results of the X-direction component on the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification (corresponding to the X-direction component of the crystal orientation).

[0035] Fig.11D It is a diagram showing the simulation results of the X-direction component (corresponding to the X-direction component of the crystal orientation) on the back side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification.

[0036] Fig.11E It is a diagram showing the simulation results of the Z-direction component (corresponding to the Y′-direction component of the crystal orientation) on the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification.

[0037] Fig.11F It is a diagram showing the simulation results of the Z-direction component (corresponding to the Y′-direction component of the crystal orientation) on the back side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification.

[0038] Fig.11G1 is a diagram showing simulation results of the Y-direction component (corresponding to the Z′-direction component of the crystal orientation) on the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification.

[0039] Fig.11H It is a diagram showing the simulation results of the Y-direction component (corresponding to the Z′-direction component of the crystal orientation) on the back side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification.

[0040] Fig.11I It is a simulation result of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification, that is, a diagram when the phase is 0°.

[0041] Fig.11J This is a simulation result of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification, that is, a diagram when the phase is set to about 45 degrees.

[0042] Figure 11K This is a simulation result of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification, that is, a diagram when the phase is set to approximately 90°.

[0043] Fig.11L This is a diagram showing the simulation result of the vibration distribution on the surface side in the thickness direction of the crystal resonator element according to the fourth modification, that is, when the phase is set to approximately 135°.

[0044] Fig.11M This is a simulation result of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification, that is, a diagram when the phase is set to approximately 180°.

[0045] Fig.11N This is a simulation result of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification, that is, a diagram when the phase is set to approximately 225°.

[0046] Fig.11O This is a simulation result of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the fourth modification, that is, a diagram when the phase is set to approximately 270°.

[0047] Fig. 12A It is a diagram showing the simulation result of the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the comparative example.

[0048] Fig. 12B It is a diagram showing the simulation result of the back side in the thickness direction of the vibration distribution in the crystal resonator element according to the comparative example.

[0049] Fig. 12CIt is a diagram showing the simulation results of the Z-direction component (corresponding to the Y′-direction component of the crystal orientation) on the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the comparative example.

[0050] Fig.12D It is a diagram showing the simulation results of the Y-direction component (corresponding to the Z′-direction component of the crystal orientation) on the surface side in the thickness direction of the vibration distribution in the crystal resonator element according to the comparative example.

[0051] Fig.13 : is a graph comparing the vibration states of the first modification example, the third modification example, the fourth modification example, and the comparative example.

[0052] Fig.14 It is a diagram showing a crystal resonator element according to a fifth modified example of the present invention.

[0053] Fig.15 It is an exploded perspective view of a crystal oscillator according to a second embodiment of the present invention.

[0054] Fig.16 yes Fig.15 XVI-XVI line section view.

[0055] Fig.17 It is an exploded perspective view of a crystal oscillator according to a third embodiment of the present invention.

[0056] Fig.18 yes Fig.17 Sectional view along line XVIII-XVIII.

[0057] Fig.19 yes Fig.14 A three-dimensional image of the crystal vibrating element shown.

[0058] Fig. 20A This is a graph for explaining the characteristics of the crystal resonator element according to the third embodiment of the present invention.

[0059] Fig. 20B This is a graph for explaining the characteristics of the crystal resonator element according to the third embodiment of the present invention.

[0060] Fig.21 This is a diagram showing an equivalent circuit of a crystal resonator element.

[0061] Fig.22A 1 is a graph for explaining the characteristics of the crystal resonator element according to the third embodiment of the present invention, and shows a case where the width W of the short side of the crystal resonator element is small.

[0062] Fig. 22B1 is a graph for explaining the characteristics of the crystal resonator element according to the third embodiment of the present invention, and shows a case where the width W of the short side of the crystal resonator element is large.

[0063] Fig.23 This is a graph for explaining the characteristics of the crystal resonator element according to the third embodiment of the present invention.

[0064] Fig.24 It is a perspective view of a crystal resonator element according to a first modified example of the third embodiment of the present invention.

[0065] Fig.25 It is a perspective view of a crystal resonator element according to a second modified example of the third embodiment of the present invention.

[0066] Fig.26 It is a perspective view of a crystal resonator element according to a third modified example of the third embodiment of the present invention.

[0067] Fig. 27 This is a perspective view of a crystal vibrating element in a crystal vibrator according to the prior art.

[0068] Fig.28 Yes means Fig. 27 A diagram showing the vibration distribution of thickness shear vibration of a crystal vibration element according to prior art. DETAILED DESCRIPTION

[0069] The following is an explanation of the embodiments of the present invention. In the following drawings, the same or similar components are represented by the same or similar symbols. The drawings are illustrative, and the size and shape of each part are schematic, and should not be understood as limiting the technical scope of the invention of this application to the embodiments.

[0070] <First embodiment>

[0071] Reference Figure 1 as well as Figure 2 , a crystal oscillator 1 according to a first embodiment of the present invention is described. Here, Figure 1 This is an exploded perspective view of a crystal oscillator. Figure 2 yes Figure 1 In addition, in Figure 2 In the figure, various electrodes of the crystal resonator element 10 are omitted.

[0072] like Figure 1 As shown, the crystal oscillator 1 according to the present embodiment includes a crystal oscillator element 10, a cover 20 as an example of a cover member, and a substrate 30 as an example of a support body for supporting the crystal oscillator element 10. The cover 20 and the substrate 30 are holders (casings or packages) for accommodating the crystal oscillator element 10.

[0073] The crystal vibrating element 10 includes a crystal piece 11, and excitation electrodes 14a and 14b (hereinafter also referred to as "first excitation electrode 14a and second excitation electrode 14b") respectively provided on the surface and back of the crystal piece 11. The first excitation electrode 14a is provided on the first surface 12a (surface) which is the principal surface of the crystal piece 11, and the second excitation electrode 14b is provided on the second surface 12b (back surface) which is the principal surface opposite to the first surface 12a of the crystal piece 11.

[0074] The crystal piece 11 has a trigonal crystal structure different from a cubic crystal structure such as piezoelectric ceramics, and is formed of a crystal material having a predetermined crystal orientation. The crystal vibrating element 10 has, for example, an AT-cut crystal piece 11. The AT-cut crystal piece 11 is formed by cutting a plane parallel to the plane defined by the X-axis and the Z'-axis (hereinafter referred to as the "XZ' plane. The same applies to the planes defined by other axes) as the main plane, while rotating the crystal axes of the artificial crystal, i.e., the Y-axis and the Z-axis among the X-axis, the Y-axis and the Z-axis around the X-axis by 35 degrees 15 minutes ± 1 minute 30 seconds from the Y-axis to the Z-axis respectively. Figure 1 In the example shown, the AT-cut crystal piece, i.e., the crystal piece 11, has a long side parallel to the X-axis as a first direction, a short side parallel to the Z' axis as a second direction orthogonal to the first direction, and a thickness parallel to the Y' axis as a third direction orthogonal to the first direction and the second direction. In addition, hereinafter, the direction along the long side is sometimes referred to as the long side direction, the direction along the short side is referred to as the short side direction, and the thickness is referred to as the thickness direction. When looking down at the XZ' plane, the crystal piece 11 is formed into a rectangle. The crystal vibrator element using the AT-cut crystal piece has extremely high frequency stability in a wide temperature range, and also has excellent time-varying characteristics. In addition, the AT-cut crystal vibrator element uses the thickness shear vibration mode (Thickness Shear Mode) as the main vibration. Below, the various structures of the crystal vibrator 1 are described based on the axial direction of the AT cut.

[0075] The crystal plate 11 involved in this embodiment is not limited to the above-mentioned structure. For example, an AT-cut crystal plate having a long side parallel to the Z' axis and a short side parallel to the X axis can be applied. Alternatively, if the main vibration is a thickness shear vibration mode, a crystal plate of a different cut other than AT-cut such as BT-cut can be used. However, AT-cut crystal plates that can obtain extremely high frequency stability in a wide temperature range are most preferred.

[0076] The first excitation electrode 14a is formed on the first surface 12a of the quartz crystal 11, and the second excitation electrode 14b is formed on the second surface 12b of the quartz crystal 11. The first and second excitation electrodes 14a and 14b are arranged as a pair of electrodes through the quartz crystal 11 so as to overlap substantially as a whole when viewed from the XZ' plane. When viewed from the XZ' plane, the first and second excitation electrodes 14a and 14b are rectangular in shape. For example, Figure 1 As shown, the long sides of the excitation electrodes are arranged to be parallel to the short sides of the crystal plate 11 , and the short sides of the excitation electrodes are arranged to be parallel to the long sides of the crystal plate 11 .

[0077] In addition, the method of the crystal resonator is not limited to the above. As a first modified example described later, Figure 4C to Figure 4E The structure of the plate-shaped quartz crystal vibrating element elongated in the X direction of the crystal orientation as shown can be implemented. That is, the long side of the excitation electrode can be parallel to the long side of the crystal plate 11, and the short side of the excitation electrode can be parallel to the short side of the crystal plate 11.

[0078] The crystal plate 11 is provided with a connection electrode 16a electrically connected to the first excitation electrode 14a via the extraction electrode 15a, and a connection electrode 16b electrically connected to the second excitation electrode 14b via the extraction electrode 15b. Specifically, the extraction electrode 15a is drawn out from the first excitation electrode 14a on the first surface 12a toward the short side on the negative direction of the X axis, and is connected to the connection electrode 16a formed on the second surface 12b through the side surface on the positive direction of the Z′ axis of the crystal plate 11. On the other hand, the extraction electrode 15b is drawn out from the second excitation electrode 14b on the second surface 12b toward the short side on the negative direction of the X axis, and is connected to the connection electrode 16b formed on the second surface 12b. The connection electrodes 16a and 16b are arranged along the short side on the negative direction of the X axis, and these connection electrodes 16a and 16b are electrically connected to the substrate 30 via the conductive holding members 36a and 36b on which the conductive adhesive is applied and cured, and are mechanically held on the substrate 30. In addition, the arrangement and pattern shape of the connection electrodes 16a, 16b and the extraction electrodes 15a, 15b are not limited, and can be appropriately changed in consideration of electrical connection with other components. In addition, in a plan view, the electrode overlap region where the first excitation electrode 14a and the second excitation electrode 14b overlap is set at a predetermined distance from the short side of the crystal plate 11. The distance from the short side of the crystal plate 11 to the electrode overlap region is greater than the distance from the long side of the crystal plate 11 to the electrode overlap region.

[0079] The first and second excitation electrodes 14a, 14b, extraction electrodes 15a, 15b, and connection electrodes 16a, 16b are formed of, for example, a chromium (Cr) layer on the surface of the crystal sheet 11 to improve bonding strength, and a gold (Au) layer is formed on the surface of the chromium layer.

[0080] like Figure 2 As shown, the cover 20 has a recessed portion 24 that is opposed to the first surface 32a of the substrate 30 and is open. In the recessed portion 24, a side wall portion 22 formed in a manner of standing up from the bottom surface of the recessed portion 24 is provided over the entire circumference of the opening. In addition, the cover 20 has a flange portion 28 that protrudes laterally from the side wall portion 22 and further outward of the opening. In this case, the flange portion 28 has an opposing surface 26 that is opposed to the first surface 32a of the substrate 30. The length of the horizontal width of the opposing surface 26 is greater than the thickness of the side wall portion 22 of the cover 20. Accordingly, by joining the flange portion 28 and the substrate 30, the joining area of ​​the two can be increased, so that the joining strength of the two can be improved.

[0081] In this embodiment, the shape of the cover 20 is not particularly limited. For example, the flange 28 may not be provided, and the front end of the side wall 22 formed standing substantially at a right angle from the bottom surface of the recess 24 may be joined to the base plate 30 .

[0082] The material of the cover 20 is not particularly limited, but can be made of a conductive material such as metal. Thus, by electrically connecting the cover 20 to the ground potential, a shielding function can be added. Alternatively, the cover 20 can be made of an insulating material or a composite structure of a conductive material and an insulating material.

[0083] The substrate 30 supports the crystal vibrating element 10 so that it can be excited. Figure 1 In the illustrated example, the crystal resonator element 10 is supported on the first surface 32 a of the substrate 30 via conductive holding members 36 a and 36 b so as to be energizable.

[0084] exist Figure 1 In the example shown, the substrate 30 has a long side parallel to the X-axis direction, a short side parallel to the Z′-axis direction, and a thickness parallel to the Y′-axis direction, and is rectangular in the XZ′ plane. The substrate 30 can be formed, for example, of insulating ceramics, for example, by stacking and firing a plurality of insulating ceramic sheets. Alternatively, the substrate 30 can be formed of a glass material (such as silicate glass, or a material with a main component other than silicate, which has a glass transition phenomenon when heated), a crystal material (such as AT-cut crystal), or a glass epoxy resin. Preferably, the substrate 30 is made of a heat-resistant material. The substrate 30 can be a single layer or a multi-layer. In the case of a multi-layer, an insulating layer can be formed on the outermost layer of the first surface 32a. In addition, the substrate 30 can be in the form of a flat plate, or in the form of a concave shape that is open in a direction opposite to the cover 20. As Figure 2As shown, the cover 20 and the substrate 30 are bonded together via the bonding material 70, so that the crystal vibrating element 10 is sealed and enclosed in the internal space (cavity) 23 surrounded by the recessed portion 24 of the cover 20 and the substrate 30. In this case, it is preferred that the pressure of the internal space is a vacuum state lower than the atmospheric pressure, because the time-dependent change caused by oxidation of the first and second excitation electrodes 14a and 14b can be reduced.

[0085] The bonding material 70 is arranged over the entire circumference of the cover 20 and the substrate 30, and is sandwiched between the opposing surface 26 of the side wall portion 22 of the cover 20 and the first surface 32a of the substrate 30. The bonding material 70 is made of an insulating material. As the insulating material, it can be a glass bonding material such as a low-melting point glass (for example, lead boric acid system, tin phosphate system, etc.), or a resin adhesive can also be used. According to these insulating materials, compared with metal bonding, it is low-cost, the heating temperature can be suppressed, and the manufacturing process can be simplified. In addition, if metal bonding is used, a higher bonding strength can be obtained than bonding using a resin adhesive.

[0086] exist Figure 2 In the example shown, one end of the crystal resonator element 10 is fixed by the conductive holding members 36a and 36b, and the other end is free. In addition, as a modified example, the crystal resonator element 10 may be fixed to the substrate 30 at both ends in either the long side or the short side.

[0087] like Figure 1 As shown, the substrate 30 includes connection electrodes 33a, 33b formed on the first surface 32a, and extraction electrodes 34a, 34b extending from the connection electrodes 33a, 33b toward the outer edge of the first surface 32a.

[0088] The connection electrode 16a of the crystal resonator element 10 is connected to the connection electrode 33a via the conductive holding member 36a, while the connection electrode 16b of the crystal resonator element 10 is connected to the connection electrode 33b via the conductive holding member 36b.

[0089] The lead electrode 34a is led out from the connection electrode 33a toward any corner of the substrate 30, and the lead electrode 34b is led out from the connection electrode 33b toward another corner of the substrate 30. In addition, a plurality of external electrodes 35a, 35b, 35c, and 35d are formed at each corner of the substrate 30. Figure 1 In the example shown, the extraction electrode 34a is connected to the external electrode 35a formed at the corner portion on the positive Z′ axis direction and the negative X axis direction, and the extraction electrode 34b is connected to the external electrode 35b formed at the corner portion on the negative Z′ axis direction and the positive X axis direction. Figure 1As shown, external electrodes 35c and 35d may be formed in the remaining corners, and these external electrodes may be dummy electrodes that are not electrically connected to the crystal oscillator element 10. That is, the dummy electrodes may not be electrically connected to the first and second excitation electrodes 14a and 14b. In addition, the dummy electrodes may be connected to terminals (terminals that are not connected to any other electronic components) provided on a mounting substrate (not shown) on which the crystal oscillator 1 is mounted. By forming such dummy electrodes, it becomes easy to provide conductive materials for forming external electrodes, and since external electrodes can be formed in all corners, it becomes easy to process the crystal oscillator electrically connected to other components. In addition, instead of dummy electrodes, the external electrodes 35c and 35d may be grounding electrodes for supplying ground potential. In the case where the cover 20 is made of a conductive material, by connecting the cover 20 to the external electrodes 35c and 35d as grounding electrodes, a shielding function can be added to the cover 20.

[0090] exist Figure 1 In the example shown, the corner of the substrate 30 has a cutout side surface formed by cutting a portion of the substrate 30 into a cylindrical curved surface shape (also called a dome shape), and the external electrodes 35a to 35d are continuously formed on the first surface 32a, the cutout side surface, and the second surface 32b. In addition, the shape of the corner of the substrate 30 is not limited to this, and the shape of the cutout may be a plane shape or a rectangular shape with no cutout and four right angles when viewed from above.

[0091] In addition, the configurations of the connection electrodes 33a, 33b, the extraction electrodes 34a, 34b, and the external electrodes 35a to d of the substrate 30 are not limited to the above examples, and various modifications can be made for application. For example, the connection electrodes 33a and 33b may be arranged on different sides of the first surface 32a of the substrate 30, such as one formed on the positive direction side of the X-axis and the other formed on the negative direction side of the X-axis. In such a structure, the crystal vibrating element 10 is supported by the substrate 30 at both one end and the other end of the long side. In addition, the number of external electrodes is not limited to four, and for example, two may be arranged at the diagonal. In addition, the external electrodes are not limited to being arranged at the corners, and may be formed on any side of the substrate 30 other than the corners. In this case, as already described, a cut side surface is formed by cutting a part of the side surface into a cylindrical curved surface, and the external electrodes are formed on the side surface other than the corners. In addition, the other external electrodes 35c and 35d as dummy electrodes may not be formed. In addition, a through hole penetrating from the first surface 32a to the second surface 32b may be formed in the substrate 30, and electrical conduction from the connection electrode formed on the first surface 32a to the second surface 32b may be achieved through a via-hole conductor provided in the through hole.

[0092] exist Figure 1In the crystal oscillator 1 shown in the figure, an alternating electric field is applied between a pair of first and second excitation electrodes 14a and 14b in the crystal oscillator element 10 via external electrodes 35a and 35b of the substrate 30. As a result, the crystal plate 11 vibrates in a thickness shear main vibration mode, and a resonance characteristic is obtained accompanying the vibration.

[0093] Next, refer to Figure 3 to Figure 14 , further describing the crystal vibration element in detail. Figure 3 is a three-dimensional diagram of the crystal vibration element 10. Figure 4A as well as Figure 4B is a diagram showing the vibration distribution of the thickness shear vibration of the crystal resonator element 10. Specifically, Figure 4A It is a schematic diagram. Figure 4B is a graph showing the simulation results. Figure 4A as well as Figure 4B In FIG. 1 , for the sake of convenience, only the vibration distribution corresponding to the first excitation electrode 14 a and the second excitation electrode 14 b is shown. Figure 4C to Figure 14 It is a diagram for explaining a crystal resonator element according to a modification example and a comparative example of the present embodiment.

[0094] Figure 3 1 is a diagram showing an example of the crystal plate 11 and the first excitation electrode 14a and the second excitation electrode 14b in the crystal resonator element 10 according to the present embodiment. In this example, when the XZ' plane is viewed from above, the short side of the excitation electrode 14a on the positive side of the Z' axis overlaps with the long side of the crystal plate 11 on the positive side of the Z' axis, and the short side of the excitation electrode 14a on the negative side of the Z' axis overlaps with the long side of the crystal plate 11 on the negative side of the Z' axis. In addition, similarly, when the XZ' plane is viewed from above, the short side of the excitation electrode 14b on the positive side of the Z' axis overlaps with the long side of the crystal plate 11 on the positive side of the Z' axis, and the short side of the excitation electrode 14b on the negative side of the Z' axis overlaps with the long side of the crystal plate 11 on the negative side of the Z' axis. That is, the excitation electrode 14a is arranged on the first surface 12a of the crystal sheet 11 to reach the two ends of the main surface of the crystal sheet 11 in the Z′ axis direction, and the excitation electrode 14b is formed on the second surface 12b of the crystal sheet 11 to reach the two ends of the main surface of the crystal sheet 11 in the Z′ axis direction.

[0095] In addition, if the length of the long side of the crystal plate 11 is set to L, the length of the short side of the crystal plate 11 is set to W, the thickness T of the crystal plate 11 in the Y′ axis direction and the length of the short side of the excitation electrode 14a in the X axis direction are set to EL, the crystal vibrating element 10 is composed of, for example, L=1.322mm, W=0.895mm, T=0.0426mm, EL=0.640mm, and G=0. G / T=0, W / T=21.0, L / T=31.0. Here, G is the distance between the short side of the excitation electrode and the long side of the crystal plate, Figure 3 The two are consistent, so G = 0. The above dimensions are just examples, and the crystal resonator element involved in this embodiment includes the following description of the vibration distribution (including the shape and size of each of the crystal plate and the excitation electrode and the positional relationship between the two).

[0096] Figure 4B Is the use of Figure 3 The simulation results obtained by implementing the piezoelectric analysis solution of the Femtet (registered trademark) software made by Murata Manufacturing Co., Ltd. on the thickness shear vibration when the crystal vibrating element 10 is subjected to an alternating electric field of a predetermined oscillation frequency, such as the AT cutting basic oscillation frequency, under the condition of a mesh size of 0.02 mm, are as follows: Figure 4A : is a schematic diagram thereof. Material constants are quoted from Chemistry Handbook Fundamentals II Revised 4th Edition, edited by the Chemical Society of Japan, Maruzen (1993), Science Chronicle 1996, edited by the National Astronomical Observatory of Japan, Maruzen (1996), Elastic Wave Component Technology Handbook, Elastic Wave Component Technology Committee 150, Japan Society for the Promotion of Science, Ohmsha, Ltd., and Surface Elastic Wave Component Material Data Book, Japan Electronics Industry Promotion Association. In addition, the above description is also applicable to the drawings showing other simulation results.

[0097] In addition, if Figure 4B As shown, the X direction of the vibration direction of the vibration distribution is equivalent to the X direction of the crystal orientation, the Y direction of the vibration direction of the vibration distribution is equivalent to the Z' direction of the crystal orientation, and the Z direction of the vibration direction of the vibration distribution is equivalent to the Y' direction of the crystal orientation. Such a relationship between the vibration direction and the crystal orientation is also applicable to other figures showing simulation results. In the following, unless otherwise specified, the direction of the crystal orientation is used as a reference for description.

[0098] like Figure 4A as well as Figure 4BAs shown in FIG. 1 , the vibration distribution of the crystal vibrating element 10 with the thickness shear vibration that mainly vibrates in the X direction as the main vibration has a vibration region 40 extending in a band shape in the Z′ axis direction (short side direction) of the crystal plate 11, and non-vibration regions 50a and 50b adjacent to both sides of the vibration region 40 in the X axis direction (long side direction) of the crystal plate 11. That is, the non-vibration regions 50a and 50b are not adjacent to each other. Here, in the present invention, the vibration region refers to a region where actual displacement occurs in the crystal plate by the thickness shear vibration, i.e., the main vibration, when an alternating electric field of a predetermined oscillation frequency (for example, the AT cut basic oscillation frequency) is applied. In addition, in the present invention, the non-vibration region refers to a region where actual displacement does not occur in the crystal plate when the vibration region of the crystal plate vibrates by the main vibration, and is not limited to a region where there is no displacement caused by the vibration, but also includes a region where the displacement caused by the vibration is smaller than that of the vibration region. In addition, as the non-vibration region, it is preferable to have a displacement amount less than 20 to 25% of the maximum displacement amount. In addition, when looking down at the XZ' plane, the vibration region 40 has a continuous strip shape from one long side parallel to the X axis of the crystal plate 11 to the other side similarly parallel to the X axis. In addition, the vibration region 40 does not reach any of the two short sides parallel to the Z' axis of the crystal plate 11. Moreover, when looking down at the XZ' plane, the boundary between the vibration region 40 and the non-vibration regions 50a, 50b is not a straight line but has a repeated wave shape of alternating hills and valleys. The wavy boundary has, for example, a roughly sinusoidal wave shape with a roughly fixed period in which the height of the hill and the depth of the valley are roughly equal. At this time, when the central part of the hill and the valley is used as a reference, it is preferred that the difference in the depth of the valley relative to the height of the hill is within ±25%. The vibration region 40 extending in a strip means that it can extend in a certain direction with a certain width, and is not limited to a shape that is elongated in the extension direction, and for example, it also includes a shape in which the length in the extension direction is less than its width.

[0099] Here, the area of ​​the vibration region 40 may be the same as that of the vibration region 40 when the XZ′ plane is viewed from above. Figure 3 The regions of the excitation electrodes 14a and 14b are substantially aligned. In this case, the vibration region 40 has a continuous strip shape from one short side parallel to the X axis of the excitation electrodes 14a and 14b to the other short side similarly parallel to the X axis. In addition, the boundary between the vibration region 40 and the non-vibration region 50a and 50b has a wave shape as described above, but is substantially aligned with the long side parallel to the Z′ axis of the excitation electrodes 14a and 14b.

[0100] Figure 4A It means in Figure 3In the structure, the vibration of the main surface shows an instantaneous displacement distribution of the maximum displacement. The vibration region 40 is divided into four equal parts based on the value of the maximum displacement, divided into three vibration regions and one non-vibration region, and different hatching lines are used to represent the vibration regions. That is, the vibration region 40 has a first vibration intensity region 42, second vibration intensity regions 44a and 44b whose vibration displacement is smaller than that of the first vibration intensity region 42, and third vibration intensity regions 46a and 46b whose vibration displacement is smaller than that of the second vibration intensity regions 44a and 44b. When looking down at the XZ′ plane, the second vibration intensity regions 44a and 44b are adjacent to both sides of the first vibration intensity region 42 in the X-axis direction (long side direction) of the crystal plate 11. In addition, the third vibration intensity regions 46a and 46b are adjacent to the side of the second vibration intensity regions 44a and 44b that is not adjacent to the first vibration intensity region 42 in the X-axis direction (long side direction) of the crystal plate 11. In other words, when a center line parallel to the Z′ axis is drawn in the center of the first vibration intensity region 42, the vibration region 40 has a line-symmetric vibration distribution based on the center line. Figure 4A The non-vibration region 50 of 0% to 25% of the maximum displacement and 0nm to 85nm is adjacent to the side of the third vibration intensity region 46a, 46b that is not adjacent to the second vibration intensity region 44a, 44b in the X-axis direction (long side direction) of the crystal plate 11. In the example shown in FIG. 4, the displacement of the first vibration intensity region 42 is 75% to 100% of the maximum displacement, which is about 255nm to 340nm, the displacement of the second vibration intensity region 44a, 44b is 50% to 75% of the maximum displacement, which is 170nm to 255nm, and the displacement of the third vibration intensity region 46a, 46b is 25% to 50% of the maximum displacement, which is 85nm to 170nm. When the XZ' plane is viewed from above, each vibration intensity region has a continuous strip shape from one long side parallel to the X-axis of the crystal plate 11 to the other long side similarly parallel to the X-axis. Furthermore, each vibration intensity region does not reach any of the two short sides parallel to the Z′ axis of the crystal plate 11. Furthermore, the boundary between adjacent vibration intensity regions is not a straight line but a wavy winding. The wavy boundary is, for example, substantially a sine wave.

[0101] Furthermore, the vibration region 40 has a strong vibration region (including the apex of vibration) showing a displacement amount of 90% or more of the maximum displacement amount. Figure 4A as well as Figure 4B As shown, the first vibration intensity region 42 in the vibration region 40 has a strong vibration region. Figure 4BAs shown, the strong vibration region has a first distribution having opposite phases to each other, namely, a long side extending in the X-axis direction located on the surface (first main surface 12a) of the crystal piece 11 and extending in the X-axis direction on the back side (second main surface 12b) of the crystal piece 11 that is separated from and opposed to the long side in the Z′-axis direction and has another long side extending in the X-axis direction. The first distribution is a semi-elliptical distribution formed by longitudinally dividing an ellipse having a major axis along the X-axis direction (long side direction) of the crystal piece 11 in half. Furthermore, the strong vibration region has a second distribution arranged along the Z′-axis direction on the surface (first main surface 12a) and the back side (second main surface 12b) of the crystal piece 11. The second distribution is as shown in FIG. Figure 4B The distribution shown is a generally elliptical shape with the major axis along the X-axis direction of the crystal plate 11. Thus, Figure 4A The first vibration intensity region 42 has a plurality of strong vibration regions along the Z′ axis direction (short side direction). Figure 4A The middle diagram shows the outer edge of the first vibration intensity region 42 including a plurality of strong vibration regions.

[0102] And, if Figure 4D As shown, the strong vibration region of the displacement component in the Z-axis direction (Y'-axis direction of the crystal orientation) based on the simulation model has a third distribution in which half of one side and half of the other side of the X-axis direction of the crystal orientation are in opposite phases to each other. More specifically, the strong vibration region also has a third distribution, which is based on a middle line extending from the midpoint of the X-axis direction of the crystal orientation of the crystal piece to the Z'-axis direction of the crystal orientation, and includes a plurality of one distribution located on one side of the X-axis direction of the middle line and arranged along the X-axis direction, and a plurality of another distribution located on the other side of the X-axis direction of the middle line and arranged along the X-axis direction and in opposite phases to the above-mentioned one distribution.

[0103] Here, in this embodiment, in a crystal piece obtained by AT-cutting a piezoelectric crystal, that is, a quartz material, which is a trigonal crystal having a predetermined crystal orientation, a vibration mode in which thickness shear is the main vibration mode is generated. Figure 4A as well as Figure 4B The new thickness shear vibration mode shown is distributed in a band along the second direction in a wavy boundary with the non-vibration area obtained in the present invention, and has a strong vibration area (including the apex or center of the vibration) where the vibrations on the edges at the diagonal positions of the front and back sides are in opposite phases to each other. Hereinafter, such a thickness shear vibration mode included in the present invention is referred to as a full-width thickness shear vibration mode. In the full-width thickness shear vibration mode, it is preferred that the strong vibration area where the vibrations on the edges at the diagonal positions of the front and back sides are in opposite phases is a semi-elliptical distribution formed by longitudinally dividing an ellipse that is longer in the X direction in half (refer to Figure 4A to Figure 4E ).

[0104] Reference here Fig. 27 as well as Fig.28 , a comparison with the conventional example is described. Fig. 27 This is a conventional crystal vibrating element in which thickness shear vibration is blocked in the center of the crystal plate. Figure 4A The difference is that the length EW of the excitation electrode in the short side direction is 0.554 mm, and the length EW is set to be less than Figure 4A , and the gap from the end surface of the crystal piece is G / T=4. That is, Fig. 27 The crystal resonator element shown includes an excitation electrode non-formation region provided in an annular shape on the outer periphery of the crystal plate, and an excitation electrode formation region provided in the center of the crystal plate and located inside the annular excitation electrode non-formation region. Fig.28 yes Fig. 27 FIG. 4 is a schematic diagram showing the vibration distribution in the thickness shear vibration mode of a conventional crystal resonator element. Fig.28 The vibration distribution is shown to include an antinode of the amplitude present in the center of the crystal piece and an amplitude node extending continuously around the entire circumference surrounding the antinode of the amplitude. In addition, when looking down at the surface of the crystal piece, the antinodes of the amplitude present on the front and back sides are at positions where they overlap with each other. Fig.28 As shown, in the crystal vibrating element of the conventional example, when looking down at the XZ′ plane, there are a first vibration intensity region in which the displacement caused by vibration is the largest, a second vibration intensity region around the first vibration intensity region in which the displacement caused by vibration is smaller than that of the first vibration intensity region, and a third vibration intensity region around the second vibration intensity region in which the displacement caused by vibration is smaller than that of the second vibration intensity region.

[0105] In contrast, the full width thickness shear vibration mode involved in this embodiment does not exist. Fig. 27 The thickness shear amplitude node or non-vibration region surrounds the center of the crystal piece in a ring shape, such as the conventional thickness shear vibration mode shown in FIG. Figure 4A As shown in FIG. 1 , there is at least one antinode of the amplitude in the vibration region that is distributed in a band shape and crosses between the two ends of the crystal piece that are opposite to each other in the second direction. In addition, when looking down at the surface of the crystal piece, the antinodes of the amplitude that exist on the front and back sides are located at positions that do not overlap with each other. Therefore, in this embodiment, Fig.28 Compared with the conventional thickness shear vibration mode with a wave antinode at the overlapping position of the front and back in the center, Figure 4A The vibration distribution shown in FIG. 1 can ensure a larger vibration area along the Z′ axis direction of the crystal plate. Furthermore, in the thickness shear vibration depending on the thickness T of the crystal plate sandwiched by the excitation electrodes, by making the length L of the crystal plate in the X axis direction greater than the length EL of the excitation electrode in the X axis direction by a predetermined ratio, not only Figure 4A The full-width thickness shear vibration mode existing in the first direction shown can also excite the full-width thickness shear vibration mode including the vibration displaced in the third direction within the vibration region in the first direction in a vibration state with multiple wavenumber distributions. In addition, if the ratio of the length L of the crystal piece in the first direction to the length EL is set within a specified range, the amplitude node extending continuously in the Z′-axis direction of the full-width thickness shear vibration mode can be arranged at the end of the crystal piece in the first direction. Therefore, if the crystal piece is supported by a retaining component at the position of the amplitude node in the full-width thickness shear vibration mode, the influence of vibration leakage and vibration obstruction on the full-width shear vibration mode caused by the support can be reduced.

[0106] As described above, in this embodiment, the vibration distribution of the thickness shear vibration is selected to generate the specific full-width thickness shear vibration referred to in the present invention throughout the Z'-axis direction (short side direction) of the crystal vibrating element 10, so that uniform vibration can be obtained. Therefore, the DLD characteristics can be improved, and in addition, by ensuring a wider vibration area 40, the CI value can be reduced and the value of the capacitance ratio γ can be reduced, so that good vibration characteristics can be obtained.

[0107] Next, refer to Figure 4C to Figure 4E The first variant is described. The following description is about the differences from the above. In this variant, the crystal resonator element is in the shape of a plate elongated in the X direction, which is different from the above. Figure 3 The same structure, but the long side direction of the excitation electrode is consistent with the long side direction of the crystal plate 11 and the short side direction of the excitation electrode is consistent with the short side direction of the crystal plate 11. Figure 3 Specifically, in this modification, W=0.277 mm, T=0.033 mm, L=0.77 mm, EL=0.44 mm, Tex=0.267 μm, G / T=0, W / T=8.39, L / T=23.7, and EL / T=12.8. Figure 4C This is a diagram of the displacement distribution of the X-direction component of the vibration distribution (equivalent to the X-direction component of the crystal orientation) obtained by simulation. Figure 4D This is a diagram of the displacement distribution of the Z-direction component of the vibration distribution (equivalent to the Y′-direction component of the crystal orientation) obtained by simulation. Figure 4E The displacement distribution diagram of the Y-direction component of the vibration distribution (equivalent to the Z'-direction component of the crystal orientation) is obtained by simulation. Figure 4CIt can be seen that the displacement distribution of the X-direction component representing the main vibration of the vibration represents the displacement distribution of the full-width thickness shear vibration of the vibration area having non-vibration areas sandwiched at both ends of the X-direction of the crystal vibration element and connecting the opposite long sides. In addition, when divided into 10 stages of displacement between the positive maximum value and the negative minimum value, the distribution state of the strong vibration area on the negative displacement side representing more than 80% of the maximum absolute value of the negative displacement showing the maximum displacement is arranged in the width direction with two elliptical distributions extending long along the X direction and a semi-elliptical distribution formed by dividing the ellipse in half longitudinally. The semi-elliptical distribution is distributed in a manner that the center is located on the long side and extends long along the long side. At this time, the maximum value of the displacement of the X-direction component is 5.668μm, the maximum value of the displacement of the Z (thickness) direction component of the vibration distribution is 0.603μm, and the maximum value of the displacement of the Y-direction (width) component of the vibration distribution is 0.966μm.

[0108] Next, refer to Figures 5 to 8 A second modification example will be described.

[0109] The crystal vibrating element 210 includes a mesa-shaped crystal piece having a first portion 240 and a second portion 250. Figure 3 to Figure 4B The vibration region described similarly has a vibration region extending in a band shape along the Z′ axis direction. When looking down at the XZ′ plane, the second part 250 is arranged at a position that is connected to each of the side parallel to the Z′ axis and the other side of the first part 240 serving as the vibration region, which is also parallel to the Z′ axis. The crystal vibrator element 210 has a first part 240 of a crystal plate sandwiched by a first excitation electrode 214a with a thickness of Tex1 and a second excitation electrode 214b with a thickness of Tex2 in the side surface of the crystal vibrator element observed from the XY′ plane. When looking down at the XY′ plane, the first part 240 has a vibration region with a thickness of T. In addition, the thickness Tpe of the second part 250 is thinner than the thickness T of the first part 240. As Figure 5 As shown, the pair of excitation electrodes 214a and 214b are respectively provided with a length EL in the X-axis direction so as to cover the entire length L1 in the X-axis direction of the vibration region of the first portion 240 located in the center of the crystal piece in the X-axis direction, and L1=EL is defined.

[0110] Figure 6 The results are shown for a vibration mode with thickness shear vibration as the main vibration mode. Figure 5 The crystal resonator element 210 shown satisfies the following equations 1 and 2 and shows a displacement distribution of vibration when a vibration mode with a wave number n=4 is excited in a vibration region having a length L1 in the X-axis direction.

[0111] In addition, the thickness of the crystal plate of the vibration region is set to T, the length of the first part in the X-axis direction is set to L1, the total thickness of the thickness Tex1 of the first excitation electrode and the thickness Tex2 of the second excitation electrode is set to Tex, the specific gravity of the material of the excitation electrode is set to γex, and the specific gravity of the material of the crystal plate is set to γxt. According to the following formula 1, the effective thickness Te of the vibration region of the crystal vibration element is given, and the effective thickness Te is calculated by adding the value of the thickness T of the crystal plate to the thickness Tex of the excitation electrode multiplied by the ratio of the specific gravity γex of the material of the excitation electrode to the specific gravity γxt of the material of the crystal plate. The wave number in the vibration region in the X-axis direction is set to n (n is a natural number). In addition, in the following formulas 1 and 2, the excitation electrode 214a and the excitation electrode 214b are made of the same material and are set to the same thickness.

[0112] Te=T+Tex·γex / γxt …Formula 1

[0113] L1 / Te=1.603·n-0.292…Equation 2

[0114] from Figure 6 It can be seen from the vibration displacement distribution that in the crystal vibrating element 210 , the vibration displacement is confined within the vibration region of the first portion 240 , and the vibration displacement of the second portion 250 is sufficiently smaller than that of the first portion 240 .

[0115] Figure 7 The displacement distribution of the vibration in the crystal vibrating element 212 formed so as to satisfy the equations 1 and 2 when n=5 is shown. Figure 7 From the vibration displacement distribution, it can be seen that when n=5, the vibration displacement is also confined within the vibration area of ​​the first part 241, and the vibration displacement of the second part 251 is sufficiently small compared to that of the first part 241.

[0116] Figure 8 is a comparative example, showing the displacement distribution of vibration in the crystal vibrating element 214 formed so as to satisfy equations 1 and 2 when n=4.5 (i.e., when n is not a natural number). Figure 8 From the vibration displacement distribution of the crystal vibration element, it can be seen that the vibration displacement is not confined within the vibration region of the first part 242, so the vibration displacement of the second part 252 is larger than that of the first part 242. Figure 6 The second part of 250 or Figure 7 The second part is 251 large.

[0117] Here, the crystal resonator element is held in the sealed space of the holder for use (see, for example, Figure 2). In general, a crystal vibrating element is held by a conductive holding component that is disposed on a substrate that is a component of the holder. Therefore, the vibration energy of the crystal vibrating element is likely to leak to the substrate via the conductive holding component. Therefore, if the crystal vibrating element can be supported by a conductive holding component at a portion where the vibration displacement is actually smaller, the vibration leakage to the substrate can be reduced. In addition, if the area of ​​the portion where the vibration displacement is actually smaller is small, the holding area of ​​the conductive holding component cannot be ensured, and the holding strength of the crystal vibrating element is reduced. As a result, stress is generated between the crystal vibrating element and the conductive holding component due to impact from a drop or changes over time, and cracks and peeling are likely to occur. In this regard, Figure 6 as well as Figure 7 The embodiment of the present invention shown is Figure 8 Compared with the comparative example shown in FIG. 1 , the non-vibration area can be arranged in almost the entire area of ​​the second portion. Figure 6 as well as Figure 7 The embodiment of the present invention shown has the effect of reducing vibration leakage and reducing cracks and peeling generated between the crystal resonator element and the conductive holding member.

[0118] Figure 5 An example is shown in which the thickness of the entire region of the second portion 250 is thinner than the thickness of the first portion 240 of the vibration region.

[0119] In addition, the form of the crystal vibrating element is not limited to the above, and as a fourth modified example described later, it is also possible to apply Fig.10 The structure shown is a structure having a first portion 243 having a thickness T, a second portion 253 adjacent to the first portion 243 at both ends of the first portion 243 in the X-axis direction, and a third portion 263 adjacent to the second portion 253 on the opposite side of the first portion 243, and a structure in which the thickness Tpe of the second portion 253 is thinner than the thickness T of the first portion 243. In this case, the thickness T of the first portion 243 and the thickness Trm of the third portion 263 may be the same. In other words, a structure in which, when viewed from the side, a groove portion (second portion 253) extending along the second direction having a thinner thickness than other portions is provided in the portion connected to both ends of the vibration region in the X-axis direction. In this case, the second portion 253 can also be set as a non-vibration region. In addition, in Fig.10 In order to facilitate understanding of the size of the crystal piece, the excitation electrode provided on the main surface on the positive side of the Y′ axis, which is one of a pair of excitation electrodes provided in the vibration region of the crystal piece with a thickness Tex, is omitted.

[0120] Patent Document 2 discloses that if the thickness of the peripheral portion of the table shape is made thinner relative to the thickness of the vibration region, bending vibration is easily excited in addition to thickness shear vibration, resulting in a decrease in energy confinement effect and difficulty in miniaturization. Specifically, when the ratio of the thickness Tpe of the peripheral portion to the thickness T of the vibration region is 0.9, Figure 8 In the same manner as in the comparative example, vibration energy leaks from the vibration region to the second portion. However, by using the structure involved in the modified example of the embodiment of the present invention, even if the ratio Tpe / T of each thickness of the peripheral portion and the vibration region is greater than 0.9, it is possible to prevent the energy confinement effect from being reduced.

[0121] As another variation, Figure 5 The structure in which the crystal plate is in a table shape may also be a structure having a first portion having a vibration region and a second portion having a thickness substantially the same as the first portion and adjacent to both ends of the first portion in the X-axis direction. Figure 3 In this case, the length EL and effective thickness Te of the excitation electrode in the X-axis direction of the vibration generating region satisfy the above equation 1 and the following equation 3.

[0122] EL / Te=1.603·n-0.292…Equation 3

[0123] It is believed that according to the structure in this case, the Figure 5 The structures shown have comparable effects.

[0124] Fig.9A as well as Fig. 9B is a diagram showing a third modified example, showing Figure 5 The same table shape simulation results. The conditions in the third variant are W = 0.277mm, T = 0.033mm, L = 0.77mm, EL = 0.44mm, D = 0.0012mm, Lt = 0.165mm, Tex = 0.267μm, G / T = 0, W / T = 8.39, L / T = 23.7, EL / T = 12.8, Tpe / T = 0.927.

[0125] Figure 10 to Figure 11O It is a diagram showing a fourth modification example. Fig.10The crystal vibrating element 216 shown in the figure includes a first portion 243 having a thickness T, a second portion 253 adjacent to the first portion 243 at both ends of the first portion 243 in the X-axis direction, and a third portion 263 adjacent to the opposite side of the first portion 243 in the second portion 253, and the second portion 253 is thinner than the first portion 243. In addition, the first portion 243 and the third portion 263 have the same thickness. Such a crystal vibrating element 216 is held on the substrate by a conductive holding member in the third portion 263 on one side, for example. The conditions in the fourth modified example are W=0.277mm, T=0.033mm, L=0.77mm, EL=0.44mm, D=0.0012mm, Lt=0.11mm, Lh=about 0.055mm, Tex=0.267μm, G / T=0, W / T=8.39, L / T=23.7, EL / T=12.8. In addition, Lh is calculated by the relationship of Lh ≒ (L-EL-2Lt) / 2.

[0126] Here, refer to Figure 11I to Figure 11O , the vibration state of the crystal vibrating element involved in the fourth variation is described. Figure 11I to Figure 11O , which is a simulation result of the surface side in the thickness direction of the vibration distribution, and is a diagram showing the vibration state when the phase is shifted from 0° to approximately 225° in units of approximately 45°. Fig.11A Similarly, the magnitude of the displacement is divided into 10 stages, and the brighter the gray scale, the larger the displacement. The phases of each figure are approximate. In addition, the position of each point of the model is proportional to the displacement of the vibration distribution.

[0127] Fig.11I This is a diagram showing the vibration state when the displacement on the negative side of the X direction (left side of the screen) of the simulation result is the maximum, with the phase being 0°. Fig.11I As shown, the maximum displacement area ( Fig.11I There are three (areas with the brightest gray scale), specifically, there are the first area, the second area, and the third area located in the approximate center of the X direction. The first area is located at the long side of the negative side of the Y direction, the second area is located away from the first area to the positive side of the Y direction, and the third area is located away from the second area to the positive side of the Y direction. The first area is in the shape of a semi-ellipse formed by longitudinally dividing an ellipse having a major axis in the X-axis direction in half. In addition, the second area and the third area are in the shape of an ellipse having a major axis in the X-axis direction. Fig.11I The maximum displacement region shown is a strong vibration region showing a displacement amount of 90% or more of the maximum displacement amount.

[0128] Fig.11J This is a diagram showing the simulation results when the phase is approximately 45°. Fig.11JIn the figure, the maximum displacement decreases, and the position of the maximum displacement area moves to the positive side of the X direction corresponding to this decrease, but the points (meshes) of the model are the same as the phase 0°. The distribution trend of the vibration is similar to the phase 0°. In addition, the position of the boundary between the vibration area and the non-vibration area is roughly the same as the phase 0°.

[0129] Figure 11K This is a diagram showing the simulation results when the phase is approximately 90°. As the phase advances, the maximum displacement decreases, and the position of the maximum displacement area moves to the positive side of the X direction. In addition, the length in the X direction in the vibration area gradually decreases as the phase advances from the phase 0°, and when the phase is approximately 90°, there is no displacement of the entire surface.

[0130] Fig.11L This is a diagram showing the simulation results when the phase is approximately 135°. If the phase advances from a phase of approximately 90°, a vibration region appears again, and as the phase advances, the length of the vibration region in the X direction increases. When the phase is approximately 135°, the position of the maximum displacement region appears in the opposite direction to the X direction of the phase of 45°.

[0131] Fig.11M This is a diagram showing the simulation results when the phase is approximately 180°. As the phase advances from approximately 135°, the maximum displacement increases, and when the phase is approximately 180°, the position of the maximum displacement region appears in the opposite direction to the X direction of the phase 0°. Fig.11M The maximum displacement region in is a strong vibration region showing a displacement amount of 90% or more of the maximum displacement amount.

[0132] Fig.11N This is a diagram showing the simulation results when the phase is approximately 225°. When the phase advances from approximately 180°, the maximum displacement decreases, and the position of the maximum displacement area moves to the negative side in the X direction. In addition, the position of the maximum displacement area is approximately the same when the phase is 0°, the phase is approximately 45°, the phase is approximately 135°, the phase is approximately 180°, and the phase is approximately 225°.

[0133] Fig.11O This is a diagram showing the simulation results when the phase is approximately 270°. As the phase advances, the maximum displacement decreases, and the position of the maximum displacement area moves to the negative side of the X direction. In addition, the length in the X direction of the vibration area gradually decreases as the phase advances from approximately 180°, and when the phase is approximately 270°, there is no displacement of the entire surface.

[0134] As described above, from the transition of the displacement distribution of the vibration, it can be seen that the vibration of this embodiment has a certain position that is always the antinode of the displacement maximum point, the displacement near the antinode becomes a semi-elliptical or elliptical vibration distribution, and the two ends in the X direction are always the nodes of the minimum displacement point, and there is a standing wave to vibrate the crystal vibration element. In addition, the position of the maximum displacement point is different from the position of the antinode at the phase 0° and approximately 180° because the displacement in each direction generated causes the position of each part of the model to be positively or negatively displaced in each direction according to the positive and negative.

[0135] FIG. 12A to FIG. 12D : is a diagram showing a comparative example. This comparative example changes the value of the length W of the short side of the crystal piece relative to the fourth variant. That is, the conditions in the comparative example are W = 0.260mm, T = 0.033mm, L = 0.77mm, EL = 0.44mm, D = 0.0012mm, Lt = 0.11mm, Lh = about 0.055mm, Tex = 0.267μm, G / T = 0, W / T = 7.88, L / T = 23.7, EL / T = 12.8.

[0136] <Evaluation>

[0137] Next, the first modification example, the third modification example, the fourth modification example, and the comparative example were evaluated. Fig.13 This is a graph comparing the vibration states of the first modification example, the third modification example, the fourth modification example, and the comparative example. In the following description of the evaluation, the XYZ axis (corresponding to the XZ′Y′ axis of the crystal orientation) of the simulation model is used as a reference.

[0138] Fig.13 This is a graph that uses the maximum amplitude intensity of the X-direction component (main vibration direction of thickness shear) of the flat plate (without a table) as the first modified example as a reference, and expresses the components of the Z-direction component as a ratio, and further expresses the ratio of the Z component to the X component as a percentage. Fig.13 , the vibration distribution of the full-width thickness shear vibration mode in the flat plate (first variant), the vibration distribution of the full-width thickness shear vibration mode in the table (third variant), the vibration distribution of the full-width thickness shear vibration mode in the table with support (fourth variant), and the vibration distribution of the non-full-width thickness shear vibration mode in the table with support. In the crystal vibration elements of the first variant, the third variant, and the fourth variant, the strong vibration region with an intensity of more than 80% of the absolute value of the maximum intensity of the amplitude component of the X-direction component is arranged along the Y direction (Z' direction of the crystal orientation) and is longer in the X direction. When looking down at the main surface of the crystal piece, the strong vibration region does not overlap on the main surface of the front and back, and the phase is reversed.

[0139] according to Fig.13, by using the table shape as the third variant, the closed state of the vibration area (table convex part) is improved, and the amplitude intensity of the X-direction component is increased by 9% compared with the flat plate. On the other hand, the Z (thickness) direction component increases from 0.11 to 0.14. As an important factor, it is believed that the simulation model assumes that the crystal piece is etched so that the step portion is not at a right angle, and the anisotropy of etching caused by the crystal orientation is considered to make the positive side of the step difference inclined on the main surface in the X direction 55 degrees and 33 degrees on the negative side, forming an asymmetric shape in the X direction. Therefore, through the asymmetry of the vibration, the vibration in the Z (thickness) direction is excited as a secondary vibration of the thickness shear vibration in the X direction.

[0140] In addition, the table with support as the fourth modification improves the closed state of the vibration area (table convex part), and the amplitude intensity of the X-direction component increases by 8% compared with the flat plate. Fig.10 ) to improve the symmetry of the shape of the step portion, thereby reducing the vibration intensity of the Z-direction component. On the other hand, although the thickness of the support portion is increased and the mass is increased, the vibration intensity of the X-direction component is 1.08, which is 8% higher than that of the flat plate, and is slightly reduced by 0.01 from the vibration intensity of the X-direction component of the table with a small mass of 1.09.

[0141] In addition, in the table with support as a comparative example, the closed state of the vibration area (table convex part) is reduced, and the amplitude intensity of the X-direction component is reduced by 6% compared with the flat plate. In addition, the vibration of the Z (thickness) direction component is excited as a secondary vibration of the thickness shear vibration in the X direction. In addition, the vibration intensity of the Z (thickness) direction component is greatly increased to 0.45, and the ratio of the Z (thickness) direction component to the X-direction component is increased to 47.6%. This is considered to be because the bending vibration in the X direction is not closed in the vibration area of ​​the thickness shear. In addition to the thickness shear vibration with the main vibration of the X direction component, the bending vibration with the main vibration of the Z direction (thickness) component is not closed in the table convex part, and the concentration of energy to the thickness shear vibration is reduced.

[0142] Furthermore, in order to evaluate the vibration leakage to the support portion of the table with support, the ratio of the maximum displacement of the thick-walled support portion (flange portion) provided at both ends of the first direction of the crystal piece to the maximum displacement in the vibration region is calculated (not shown). In the case of the fourth variant, it becomes 0.03, and in the case of a simple thickness shear vibration (W / T=7.88) which is not a full-width thickness shear vibration as a comparison example, it becomes 0.17. Thus, by implementing the full-width thickness shear vibration, compared with the simple thickness shear vibration, a non-vibration region is not provided on both sides of the excitation electrode of the crystal piece in the width direction, and the effect of reducing the vibration leakage from the vibration region is obtained.

[0143] Next, refer to Fig.14 A fifth modification of the crystal resonator element 60 will be described. The following describes points different from the above.

[0144] The crystal vibrating element 60 includes a crystal piece 61, a first excitation electrode 64a provided on a first surface 62a (front surface) which is a principal surface of the crystal piece 61, and a second excitation electrode 64b provided on a second surface 62b (back surface) which is a principal surface opposite to the first surface 62a of the crystal piece 61.

[0145] In this example, when looking down at the XZ' plane, the short side of the first excitation electrode 64a on the positive Z' axis side is provided with a gap from the long side of the crystal plate 61 on the positive Z' axis side. In addition, the short side of the first excitation electrode 64a on the negative Z' axis side is provided with a gap from the long side of the crystal plate 61 on the negative Z' axis side.

[0146] In addition, the second excitation electrode 64b is similarly provided such that, when the XZ' plane is viewed from above, the short side of the second excitation electrode 64b on the positive Z' axis side is provided with a gap from the long side of the crystal plate 61 on the positive Z' axis side. In addition, the short side of the second excitation electrode 64b on the negative Z' axis side is provided with a gap from the long side of the crystal plate 61 on the negative Z' axis side.

[0147] That is, the short sides of the first excitation electrode 64a are provided on the first surface 62a of the crystal plate 61 with gaps from the long sides of the crystal plate 61 on both sides. On the other hand, the short sides of the second excitation electrode 64b are provided on the second surface 62b of the crystal plate 61 with gaps from the long sides of the crystal plate 61 on both sides. The size G of these gaps is, for example, 0<G≤20μm. In addition, it is preferred that the size G of the gap from the edge of the side surface in the X direction is within the range in which an electric field is applied to the side surface in the Z′ axis direction of the crystal plate 61 by the alternating electric field between the first excitation electrode 64a and the second excitation electrode 64b.

[0148] It is preferable that the size G of the slit is substantially the same on one side of the excitation electrode. In addition, it is preferable that the size G of the slit is substantially the same on one side and the other side of the first excitation electrode 64a, and it is also preferable that the size G of the slit is substantially the same on one side and the other side of the second excitation electrode 64b. In addition, as a modified example, the size G of the slit may be partially different on one side of the excitation electrode. In addition, it may be different on one side and the other side of any one of the first excitation electrode 64a and the second excitation electrode 64b.

[0149] In this modification, a vibration mode is generated in which thickness shear vibration is the main vibration when an alternating electric field of a predetermined oscillation frequency, such as the AT cutting basic oscillation frequency, is applied, and its vibration distribution is similar to that based on Figure 4A The contents described are essentially the same. Figure 4A In the same manner as the vibration region 40 shown in FIG. 1 , when looking down at the XZ′ plane, the crystal plate 61 extends in a strip shape along the Z′ axis direction to a position greater than 1. Fig.14 The short sides of the first excitation electrode 64a and the second excitation electrode 64b shown in FIG. Fig.14 The vibration region generated by the first excitation electrode 64a and the second excitation electrode 64b has a continuous strip shape from one long side parallel to the X-axis direction of the crystal plate 61 to the other long side also parallel to the X-axis direction. However, in this modification, adjacent to both sides of the vibration region along the X-axis direction of the crystal plate 61 Figure 4A Non-vibration areas 50a, 50b are shown.

[0150] In addition, as already described, the connection electrode 66 a electrically connected to the first excitation electrode 64 a via the extraction electrode 65 a and the connection electrode 66 b electrically connected to the second excitation electrode 64 b via the extraction electrode 65 b are formed in the crystal piece 61 .

[0151] As described above, in the modification according to the present embodiment, since the full-width thickness shear vibration mode is generated along the Z′-axis direction of the crystal plate 61 , good vibration characteristics can be obtained.

[0152] <Second embodiment>

[0153] Next, refer to Fig.15 as well as Fig.16 , the crystal oscillator 2 according to the second embodiment of the present invention is described. Here, Fig.15 This is an exploded perspective view of the crystal oscillator 2. Fig.16 yes Fig.15 In this embodiment, the package form of the crystal oscillator 2 is different from that of the first embodiment, and the shape, size and positional relationship of the crystal plate 102, the first excitation electrode 114a and the second excitation electrode 114b in the crystal oscillator element 110 can adopt the same structure as that of the first embodiment. The following describes the differences from the first embodiment.

[0154] like Fig.15 As shown, the crystal vibrator 2 of the present embodiment includes a crystal vibrating element 110 , a first substrate 120 , and a second substrate 130 .

[0155] In this modification, the first and second substrates 120 and 130 are shells or packages for accommodating the crystal piece 102 of the crystal vibrating element 110. The crystal vibrating element 110, the first substrate 120, and the second substrate 130 have substantially the same size and shape (rectangular shape) in the XZ′ plane. In the case of a manufacturing method that directly performs packaging of the crystal piece from the wafer state, such as a wafer level chip size package (hereinafter referred to as “WLCSP”), a three-layer structure consisting of a wafer corresponding to the first substrate 120, a wafer corresponding to the crystal vibrating element 110, and a wafer corresponding to the second substrate 130 is processed together and divided into individual crystal vibrators 2 using a cutting machine for manufacturing. Therefore, the crystal vibrating element 110, the first substrate 120, and the second substrate 130 have substantially the same size and shape.

[0156] The crystal vibrating element 110 includes a crystal piece 102, a frame 104 surrounding the outer periphery of the crystal piece 102, and connecting parts 118a and 118b connecting the crystal piece 102 and the frame 104. The frame 104 is an example of a support for supporting the crystal piece 102. The crystal piece 102, the frame 104, and the connecting parts 118a and 118b are all formed of a crystal material having a predetermined crystal orientation, for example, an AT-cut crystal material.

[0157] Although the thickness of the crystal vibrating element 110 in the Y′-axis direction is not particularly limited, for example, Fig.16 As shown, the thickness of the crystal plate 102, the frame 104 and the connecting parts 118a, 118b can all be the same. Alternatively, as a structure similar to a table structure, in order to improve the sealing of vibration energy, the thickness of the connecting parts 118a, 118b can be thinner than the crystal plate 102.

[0158] The crystal vibrating element 110 has a long side in the X-axis direction, a short side in the Z′-axis direction, and a thickness in the Y′-axis direction. Fig.15 In the example shown, the connecting members 118a and 118b are both arranged at one end of the long side of the crystal plate 102 on the X-axis direction side. The crystal plate 102 and the frame 104 are arranged to be separated and connected by the connecting members 118a and 118b. Fig.15 In the example shown, two connecting members are arranged at one end of the long side, but there is no particular limitation on the number of connecting members, their arrangement, etc. For example, the connecting member may be a single connecting member arranged at one end of the long side, or one of the two connecting members may be arranged at one end of the long side and the other may be arranged at the other end of the long side.

[0159] The crystal vibrating element 110 has cutout side surfaces 108a, 108b, 108c, and 108d formed by cutting off a part of the corner into a cylindrical curved surface. Similarly, cutout side surfaces 122a, 122b, 122c, and 122d are also formed in the first substrate 120, and cutout side surfaces 132a, 132b, 132c, and 132d are also formed in the second substrate 130. Such cutout side surfaces are formed along with a manufacturing method that directly performs packaging from a wafer state using WLCSP or the like. In this case, among the cutout side surfaces of the crystal vibrating element 110, the first substrate 120, and the second substrate 130, for example, the cutout side surfaces 108a, 122a, and 132a are respectively formed in accordance with the Y′ axis direction. In addition, the shape of the cutout side surface may be a shape other than a cylindrical curved surface, or there may be no such cutout.

[0160] The first and second excitation electrodes 114a and 114b are formed on the front and back sides of the quartz crystal 102, respectively. The first excitation electrode 114a is provided on the first surface 112a (front side) of the quartz crystal 102, and the second excitation electrode 114b is provided on the second surface 112b (back side) opposite to the first surface 112a of the quartz crystal 102. The first and second excitation electrodes 114a and 114b are arranged as a pair of electrodes so as to overlap substantially as a whole through the quartz crystal 102 when viewed from above the XZ′ plane. Each of the excitation electrodes 114a and 114b has a rectangular shape in the XZ′ plane, for example, Fig.15 As shown, the long sides of the excitation electrodes are arranged in parallel with the short sides of the crystal plate 102 , and the short sides of the excitation electrodes are arranged in parallel with the long sides of the crystal plate 102 .

[0161] An extraction electrode 115a electrically connected to the first excitation electrode 114a is formed on the first surface 111a of the frame 104. The extraction electrode 115a is extracted from the first excitation electrode 114a through a connecting component 118a on one side, and then is extracted toward the cut side surface 108a on the first surface 111a of the frame 104, and is electrically connected to the connection electrode 116a formed on the second surface 111b of the frame 104. On the other hand, an extraction electrode 115b electrically connected to the second excitation electrode 114b is formed on the second surface 111b of the frame 104. The extraction electrode 115b is extracted from the second excitation electrode 114b through a connecting component 118b on the other side, and then is extended and protruded toward the cut side surface 108b in the corner through the second surface 111b of the frame 104, and is electrically connected to the connection electrode 116b formed on the second surface 111b of the frame 104. In this way, Fig.15 In the illustrated example, connection electrodes 116 a and 116 b electrically connected to the first and second excitation electrodes 114 a and 114 b are arranged at opposing corners of the frame body 104 .

[0162] Furthermore, the arrangement of the connection electrodes 116a and 116b electrically connected to the first and second excitation electrodes 114a and 114b is not particularly limited, and they may be arranged at two corners on the negative side of the frame body 104 in the X-axis direction, namely, the cutout side surfaces 108d and 108b.

[0163] The first and second excitation electrodes 114a and 114b, the extraction electrodes 115a and 115b, and the connection electrodes 116a and 116b may be formed of, for example, a chromium (Cr) layer as a base and a gold (Au) layer formed on the surface of the chromium layer, and the material thereof is not limited.

[0164] The first substrate 120 is disposed on the first surface 112a side of the quartz crystal 102. In addition, the second substrate 130 is disposed on the second surface 112b side of the quartz crystal 102. That is, the first substrate 120, the crystal vibrating element 110, and the second substrate 130 are stacked in sequence to form a three-layer structure. The second substrate 130 has a mounting surface on which the crystal vibrating element 110 is mounted, and a mounting surface that is opposite to the mounting surface and is electrically connected to the outside.

[0165] On the mounting surface of the second substrate 130, external electrodes 134a, 134b, 134c, and 134d are formed at each corner. When the crystal vibrating element 110 is mounted on the second substrate 130, the external electrode 134a is electrically connected to the first excitation electrode 114a via the connecting electrode 116a and the extraction electrode 115a. Thus, the external electrode 134b is electrically connected to the second excitation electrode 114b via the connecting electrode 116b and the extraction electrode 115b. The remaining external electrodes 134c and 134d may be dummy electrodes that are not electrically connected to any of the first and second excitation electrodes 114a and 114b. The details of the dummy electrodes are as described above.

[0166] In addition, Fig.15 In the example shown, the external electrodes 134a and 134b electrically connected to the first and second excitation electrodes 114a and 114b are arranged at opposite corners of the second substrate 130, but the present invention is not limited thereto and the external electrodes 134a and 134b may be arranged at other corners. In addition, when the corners of the second substrate 130 form a cylindrical curved cutout side surface, the external electrodes may extend and protrude from the mounting surface of the second substrate 130 to the cutout side surface at the corresponding corners.

[0167] The external electrodes 134a to 134d are formed of, for example, chromium (Cr), gold (Au), etc. The formation method uses a sputtering method or a plating method. In addition, in this embodiment, a 4-terminal structure consisting of 4 external electrodes is shown, but the number of external electrodes is not particularly limited, and for example, a 2-terminal structure consisting of two external electrodes can be applied.

[0168] The first and second substrates 120 and 130 are flat substrates. In addition, the first and second substrates 120 and 130 may be made of glass (e.g., silicate glass, or a material with a main component other than silicate that has a glass transition phenomenon when heated), or may be made of the same material as the crystal vibrating element 110, that is, crystal (e.g., AT-cut crystal).

[0169] like Fig.15 as well as Fig.16 As shown, the first substrate 120 is bonded to the entire circumference of the first surface 111a of the frame 104 via the first bonding material 140, and the second substrate 130 is bonded to the entire circumference of the second surface 111b of the frame 104 via the second bonding material 142. By arranging the first and second bonding materials 140 and 142 on the entire circumference of each surface of the frame 104, the crystal plate 102 is sealed in the internal space (cavity) 123. The first and second bonding materials 140 and 142 are not limited in material as long as they can bond the bonding surfaces of each component to each other and seal in a manner to form an internal space. The first and second bonding materials 140 and 142 can be, for example, glass bonding materials such as low-melting point glass (such as lead boric acid system, tin phosphate system, etc.), or resin adhesives can be used.

[0170] The structures of the crystal plate 102 and the first excitation electrode 114a and the second excitation electrode 114b in the crystal vibrating element 110 according to this embodiment can be applied to the contents described in the first embodiment (see Figure 1 to Figure 14 According to the crystal resonator 2 of this embodiment, since the full-width thickness shear vibration mode is generated along the Z′-axis direction of the crystal plate 102 , good vibration characteristics can be obtained.

[0171] <Third embodiment>

[0172] Reference Fig.17 as well as Fig.18 , a crystal oscillator according to an embodiment of the present invention is described. Here, Fig.17 This is an exploded perspective view of a crystal oscillator. Fig.18 yes Fig.17 In addition, Fig.18 The illustration of various electrodes of the crystal oscillator element is omitted.

[0173] Hereinafter, the structure of the crystal oscillator according to the present embodiment will be described. Hereinafter, as long as there is no contradiction with the contents described in the first and second embodiments, the contents described in these embodiments can be selectively applied as appropriate.

[0174] like Fig.17As shown, the crystal vibrator 1001 according to this embodiment includes a crystal vibrating element 1100 , a cover 1200 , and a substrate 1300 . The cover 1200 and the substrate 1300 are holders (casings or packages) for housing the crystal vibrating element 1100 .

[0175] The crystal vibrating element 1100 includes a crystal piece 1110, and excitation electrodes 1120 and 1130 (hereinafter also referred to as "first and second excitation electrodes 1120 and 1130") respectively provided on the front and back surfaces of the crystal piece 1110. The first excitation electrode 1120 is provided on the first surface 1112 (front surface) which is the main surface of the crystal piece 1110. The second excitation electrode 1130 is provided on the second surface 1114 (back surface) which is the main surface opposite to the first surface 1112 of the crystal piece 1110.

[0176] The crystal structure, cut angle, and other structures of the crystal piece 1110 can be applied to the crystal piece 11 described in the first embodiment. Fig.17 In the example shown, the crystal piece 1110 is an AT-cut crystal piece. The AT-cut crystal piece 1110 has a long side parallel to the X-axis, a short side parallel to the Z' axis, and a thickness parallel to the Y' axis. In addition, hereinafter, the long side is sometimes referred to as the long side direction, the short side is referred to as the short side direction, and the thickness is referred to as the thickness direction. In addition, the AT-cut crystal piece 1110 is rectangular when viewed from the XZ' plane.

[0177] The crystal piece involved in this embodiment is not limited to the above structure, and for example, an AT-cut crystal piece having a long side parallel to the Z' axis and a short side parallel to the X-axis direction can be applied. Alternatively, as long as the main vibration is a thickness shear vibration mode, a crystal piece of a different cut other than AT-cut such as BT-cut can be used.

[0178] The first excitation electrode 1120 is formed on the first surface 1112 (XZ' surface on the positive side of the Y' axis) of the crystal plate 1110, and the second excitation electrode 1130 is formed on the second surface 1114 (XZ' surface on the negative side of the Y' axis) of the crystal plate 1110 opposite to the first surface 1112. The first and second excitation electrodes 1120 and 1130 are arranged as a pair of electrodes so as to overlap substantially as a whole through the crystal plate 1110 when viewed from above the XZ' plane. The first and second excitation electrodes 1120 and 1130 are rectangular in the XZ' plane. In addition, the long sides of the excitation electrodes are parallel to the long sides of the crystal plate 1110, and the short sides of the excitation electrodes are parallel to the short sides of the crystal plate 1110. In addition, the details of each structure of the crystal plate 1110 and each of the excitation electrodes 1120 and 1130 will be described later.

[0179] The crystal plate 1110 includes a connection electrode 1124 electrically connected to the first excitation electrode 1120 via the extraction electrode 1122, and a connection electrode 1134 electrically connected to the second excitation electrode 1130 via the extraction electrode 1132. Specifically, the extraction electrode 1122 is drawn out from the first excitation electrode 1120 on the first surface 1112 toward the short side on the negative direction of the X axis, and is connected to the connection electrode 1124 formed on the second surface 1114 through the side surface on the negative direction of the X axis of the crystal plate 1110. On the other hand, the extraction electrode 1132 is drawn out from the second excitation electrode 1130 on the second surface 1114 toward the short side on the negative direction of the X axis, and is connected to the connection electrode 1134 formed on the second surface 1114. The connection electrodes 1124 and 1134 are arranged along the short side on the negative side of the X-axis, and these connection electrodes 1124 and 1134 are electrically connected to the substrate 1300 via the conductive holding members 1340 and 1342 described later, and are mechanically held on the substrate 1300. In addition, in this embodiment, the arrangement and pattern shape of the connection electrodes 1124 and 1134 and the extraction electrodes 1122 and 1132 are not limited, and can be appropriately changed in consideration of electrical connection with other components.

[0180] The first and second excitation electrodes 1120 and 1130 , the extraction electrodes 1122 and 1132 , and the connection electrodes 1124 and 1134 may be formed of, for example, a chromium (Cr) layer as a base, and a gold (Au) layer formed on the surface of the chromium layer, and the materials thereof are not limited.

[0181] like Fig.18 As shown, the cover 1200 has a recessed portion 1204 that opens to face the first surface 1302 of the substrate 1300. In the recessed portion 1204, a side wall portion 1202 formed in a manner of standing up from the bottom surface of the recessed portion 1204 is provided over the entire circumference of the opening, and the side wall portion 1202 has an end surface 1205 that faces the first surface 1302 of the substrate 1300.

[0182] Although the material of the cover 1200 is not particularly limited, it can be made of metal, for example. Thus, by electrically connecting the cover 1200 to the ground potential, a shielding function can be added. Alternatively, the cover 1200 can also be an insulating material or a composite structure of metal and insulating material.

[0183] In addition, as a modified example, the cover 1200 may have a flange portion that protrudes laterally from the side wall portion 1202 to the outside of the opening. According to this, by joining the flange portion and the substrate 1300, the joining area of ​​the two can be increased, so that the joining strength of the two can be improved.

[0184] The crystal vibrating element 1100 is mounted on the first surface 1302 (upper surface) of the substrate 1300. Fig.17In the example shown, the substrate 1300 has a long side parallel to the X-axis, a short side parallel to the Z′ axis, and a thickness parallel to the Y′ axis, and is rectangular in the XZ′ plane. The substrate 1300 can be formed, for example, of insulating ceramics, and can be formed by stacking and firing a plurality of insulating ceramic sheets. Alternatively, the substrate 1300 can be formed of a glass material, a crystal material, or a glass epoxy resin. Preferably, the substrate 1300 is made of a heat-resistant material. The substrate 1300 can be a single layer or a multi-layer. In the case of a multi-layer, an insulating layer can be formed on the outermost layer of the first surface 1302. In addition, the substrate 1300 can be in the form of a flat plate, or can be in the form of a concave shape that is open in a direction opposite to the cover 1200. As Fig.17 As shown, the cover 1200 and the substrate 1300 are bonded together via a bonding material 1350 , so that the crystal vibrating element 1100 is sealed in an internal space (cavity) 1206 surrounded by a recess 1204 of the cover 1200 and the substrate 1300 .

[0185] The bonding material 1350 is provided over the entire circumference of the cover 1200 and the substrate 1300, and is sandwiched between the end surface 1205 of the side wall portion 1202 of the cover 1200 and the first surface 1302 of the substrate 1300. The bonding material 1350 is made of an insulating material. As the insulating material, for example, it can be a glass material (for example, a low melting point glass), or it can be a resin material (for example, an epoxy resin). These insulating materials have a lower melting point and are also low-cost compared to metal materials. Therefore, by using these insulating materials for the bonding material 1350, the heating temperature in the bonding process of the cover 1200 and the substrate 1300 can be suppressed, and the cost of the crystal oscillator can also be reduced.

[0186] exist Fig.18 In the example shown, one end of the crystal vibrating element 1100 (the end on the conductive holding member 1340, 1342 side) is a fixed end, and the other end is a free end. In addition, as a modified example, the crystal vibrating element 1100 may be fixed to the substrate 1300 at both ends in the longitudinal direction.

[0187] like Fig.17 As shown, the substrate 1300 includes connection electrodes 1320, 1322 formed on the first surface 1302, and extraction electrodes 1320a, 1322a extending from the connection electrodes 1320, 1322 toward the outer edge of the first surface 1302. The connection electrodes 1320, 1322 are arranged on the inner side than the outer edge of the substrate 1300 so that the crystal vibrating element 1100 can be arranged at the approximate center of the first surface 1302 of the substrate 1300.

[0188] The connection electrode 1124 of the crystal vibrating element 1100 is connected to the connection electrode 1320 via the conductive holding member 1340 , and the connection electrode 1134 of the crystal vibrating element 1100 is connected to the connection electrode 1322 via the conductive holding member 1342 .

[0189] The lead electrode 1320a is led out from the connection electrode 1320 toward any corner of the substrate 1300, and the lead electrode 1322a is led out from the connection electrode 1322 toward another corner of the substrate 1300. In addition, a plurality of external electrodes 1330, 1332, 1334, and 1336 are formed at each corner of the substrate 1300. Fig.17 In the example shown, the extraction electrode 1320a is connected to the external electrode 1330 formed at the corner on the positive Z′ axis and the negative X axis side, and the extraction electrode 1322a is connected to the external electrode 1332 formed at the corner on the negative Z′ axis and the positive X axis side. Fig.17 As shown, external electrodes 1334 and 1336 may also be formed in the remaining corners. These external electrodes may be used as the dummy electrodes described above. In this case, by electrically connecting the cover 1200 made of a conductive material to the external electrodes 1334 and 1336 as dummy electrodes, a shielding function may be added to the cover 1200.

[0190] exist Fig.17 In the example shown, the corner of the substrate 1300 has a cutout side surface formed by cutting a portion of the substrate 1300 into a cylindrical curved surface shape, and the external electrodes 1330, 1332, 1334, and 1336 are continuously formed on the first surface 1302, the cutout side surface, and the second surface 1304. In addition, the shape of the corner of the substrate 1300 is not limited to this, and the shape of the cutout may be a plane shape, or may be a rectangular shape with four right angles when viewed from above without a cutout.

[0191] In addition, the structures of the connection electrodes, extraction electrodes, and external electrodes of the substrate 1300 are not limited to the above examples, and various modifications can be applied. For example, the connection electrodes 1320 and 1322 can also be formed on the positive direction side of the X-axis and the other side on the negative direction side of the X-axis, and can be arranged on different sides on the first surface 1302 of the substrate 1300. In such a structure, the crystal vibrating element 1100 is supported by the substrate 1300 at both one end and the other end in the long side direction. In addition, the number and arrangement of the external electrodes, the presence or absence of dummy electrodes, and the electrical connection form of the external electrodes and the connection electrodes can apply the contents already described.

[0192] exist Fig.17In the crystal oscillator 1001 shown, an AC voltage is applied between a pair of first and second excitation electrodes 1120 and 1130 in the crystal vibrating element 1100 via external electrodes 1330 and 1332, so that the crystal piece 1110 vibrates in a thickness shear main vibration mode, obtaining the resonance characteristics generated by the vibration.

[0193] Next, refer to Figure 19 to Figure 21 , further elaborated Fig.17 The crystal vibrating element shown. Fig.19 Yes means Fig.17 The diagram shows a crystal piece and an excitation electrode on the first surface of a crystal resonator element (for ease of explanation, the lead electrodes and connecting electrodes are omitted). Fig. 20A as well as Fig. 20B This is a graph for explaining the characteristics of a crystal oscillator. Fig.21 This is a diagram showing an equivalent circuit of a crystal resonator element.

[0194] like Fig.19 As shown, on the positive side of the Z′ axis, the long edge 1120a of the excitation electrode 1120 is parallel to the long edge 1112a on the positive side of the Z′ axis of the crystal plate 1110, and when the distance between the long edge 1120a of the excitation electrode 1120 and the long edge 1112a of the crystal plate 1110 is G, and the thickness between the excitation electrodes 1120 and 1130 in the crystal plate 1110 is T, the relationship of 0.0002≤G / T≤0.5 is satisfied. In other words, the long edge 1120a of the excitation electrode 1120 is spaced inwardly by a distance G from the long edge 1112a of the crystal plate 1110, and the distance G has the above-mentioned relationship with respect to the thickness T of the crystal plate 1110.

[0195] According to this, the edges of the main surfaces of the crystal plate 1110 may be easily damaged during the manufacturing process, resulting in material changes. By setting the lower limit of the above relationship, the deterioration of the vibration characteristics caused by such damage can be suppressed. On the other hand, if the distance G is too large, the unnecessary area that does not contribute to the vibration will be expanded. Therefore, by setting the upper limit of the above relationship, the miniaturization of the crystal vibration element is achieved, and the effective area of ​​the excitation electrode is ensured.

[0196] In addition, it is known that if the capacitance of the equivalent circuit of the crystal resonator is relatively small, good vibration characteristics will be obtained. Fig.21 As shown, in the equivalent circuit of the crystal resonator element in which the equivalent series resistor R1, the equivalent series capacitor C1, and the equivalent inductor L1 are connected in series and the equivalent parallel capacitor C0 is connected in parallel, if the capacitance ratio C0 / C1=γ is smaller, the frequency sensitivity of the crystal resonator element can be increased.

[0197] For this, if you try to use Fig. 20A as well as Fig. 20B To observe the relationship between G / T and capacitance ratio γ, we can know that Fig. 20A As shown in FIG. 1 , there is a critical point where the rate of increase of the capacitance ratio γ increases near G / T=0.5. On the other hand, it can be seen that Fig. 20B (shown Fig. 20A ), when G / T is less than 0.0002 and close to 0.0001, the capacitance ratio γ also changes in a manner that increases. That is, it can be seen that the capacitance ratio γ can be reduced by having the above-mentioned relationship between G / T. Moreover, by reducing the capacitance ratio γ, the frequency sensitivity of the crystal vibrating element can be increased, which can improve the frequency controllability of the crystal vibrating element to obtain good vibration characteristics. Furthermore, if an excitation electrode is set in the range where G / T is less than 0.0002 from the end face of the crystal piece, in addition to the influence of the change in the capacitance ratio γ, it is also affected by the instability of the end face shape of the crystal piece. Therefore, it is preferred to set the excitation electrode on the crystal piece in a manner such that G / T becomes greater than 0.0002.

[0198] In addition, if Fig. 20A As shown, since there is a critical point where the rate of increase of the capacitance ratio γ becomes large near G / T=0.2 (between 0.2 and 0.3), it is more preferable to have a relationship of G / T≤0.2.

[0199] Furthermore, if the relationship of 0.0002≤G / T≤0.2 is satisfied, the capacitance ratio γ is small and can be stably set, which is most preferable.

[0200] The above-described relationship about G / T is also applicable to the relationship between the long edge 1120b of the excitation electrode 1120 on the negative side of the Z′ axis and the long edge 1112b on the negative side of the Z′ axis of the crystal plate 1110. In addition, in the above description, the excitation electrode 1120 on the first surface 1112 of the crystal plate 1110 is described, but the same is also applicable to the long side on the second surface 1114 side of the crystal plate 1110. In addition, the above-described relationship is applied to the long side of the crystal plate 1110 because the longer the long side is, the greater the influence on the vibration characteristics of the crystal vibration element is compared with the shorter side.

[0201] In addition, if the width of the short side of the crystal plate 1110 is set to W, the relationship W / T≦10.2 can also be satisfied. The technical significance of this relationship will be described below.

[0202] In a crystal resonator element, in addition to the main vibration, resonance is also generated due to parasitics (useless vibrations) caused by the shape and size. The resonance caused by the parasitic appears as a larger or smaller depression (depression) in the impedance curve. If there is a depression near the main vibration, the oscillation frequency may shift, the resonance resistance may increase, and the margin relative to the oscillation may decrease, which may have a negative impact on the crystal resonator element. Here, in a rectangular crystal resonator element such as the present embodiment, when the width of the short side is set to W and the thickness of the crystal piece is set to T, the parasitic is a width vibration related to W / T, and exists in large quantities as a multiple mode. Such parasitics are called width parasitics. If you try to observe the width parasitics near the main vibration, when W is small, such as Fig.22A In this way, the frequency interval of the width parasitic becomes larger, and when W is large, such as Fig. 22B In this way, the frequency interval of the width parasitic becomes smaller. And if we try to observe the change with temperature change, in AT-cut crystal wafers, the main vibration changes as a cubic function with the temperature change from 0°C to 50°C, more specifically, it changes in the range of about 10ppm, while the width parasitic changes as a linear function with a smaller value, more specifically, it changes by about 1.0%. If we observe the width parasitic with temperature change in this way, the change of the main vibration can be relatively ignored.

[0203] Reference Fig.23 , W / T, which is less affected by parasitic vibration due to temperature change, is described. Here, Fig.23 The graph has W / T as the horizontal axis and ΔF / ΔP (parasitic density) as the vertical axis. The temperature change condition is 0° C. to 50° C., which is the main operating temperature of the electronic device.

[0204] Specifically Fig.23To explain. First, by using the finite element method analysis, the W / T is changed at room temperature to investigate the frequency and number of width parasitics at the frequencies before and after the main vibration, and the average frequency interval ΔP (MHz) between adjacent parasitics is calculated. In addition, as a condition, W=430 (W / T=10.35) is extracted at a frequency of 37.4MHz, and the analysis is performed by changing the temperature from 0°C to 50°C. Based on the analysis results, for 10 width parasitics before and after the main vibration, the variation of the parasitics when changing from 0°C to 50°C is calculated, and the average value ΔF (MHz) is calculated. That is, at each W / T, the frequency of the width parasitic has a variation width of ΔF according to the temperature change. Moreover, if the frequency interval ΔP of the two width parasitics sandwiching the main vibration is less than ΔF, then with respect to the temperature change, at least one of the adjacent width parasitics may cross the main vibration. Thus, in each W / T, if the frequency interval ΔP of adjacent width parasitics is smaller than ΔF, the possibility of width parasitics crossing the main vibration becomes larger, and depending on the situation, the width parasitics may cross multiple frequencies and cause the characteristics to deteriorate sharply. Fig.23 As shown, ΔF / ΔP≤1, in other words, the interval between the two width parasitics adjacent to the main vibration is smaller than the area of ​​W / T that is consistent with the variation width from 0°C to 50°C (i.e., as Fig.23 As shown in FIG. 1 , when W / T≤10.2), it is possible to design a width parasitic so that it does not cross the main vibration. Specifically, the possibility of a design in which the excitation frequency of the main vibration and the frequency of the width parasitic are inconsistent becomes higher, and the risk of the smaller side crossing becomes less. In addition, the position of the width parasitic can also be slightly changed by performing a bevel or convex surface processing on the crystal piece. Therefore, when W / T≤10.2, by further performing a bevel or convex surface processing to simulate reducing the width dimension, the risk of the width parasitic crossing the main vibration can also be further reduced.

[0205] In addition, the length L of each long side of the crystal piece 1110 may be appropriately selected in consideration of desired vibration characteristics and the like.

[0206] According to this embodiment, since the relationship between the distance G between the long edge 1112a of the crystal piece 1110 and the long edge 1120a of the excitation electrode 1120 and the thickness T between each excitation electrode 1120 and 1130 in the crystal piece 1110 satisfies the above-mentioned relationship, good vibration characteristics can be obtained as already described.

[0207] The present invention is not limited to the above-described embodiment and can be applied in various modifications. In addition, in the following description, points different from the above-described contents are described, and the same structures as the above-described contents are given the same reference numerals in the drawings.

[0208] Reference Figure 24 to Figure 26, a crystal vibrating element according to a modified example of the present embodiment will be described. In each of the following modified examples, the structure of the crystal plate is different from the above-mentioned content.

[0209] Fig.24 1 is a diagram for explaining a crystal resonator element according to a first modification example. In this example, a crystal piece having a so-called mesa structure in the long-side direction is provided.

[0210] The crystal plate 1410 of the crystal vibrating element 1400 according to this modification includes a vibrating portion 1402 in which excitation electrodes 1420 and 1430 overlap each other, and thin-walled end portions 1404 and 1406 connected to the vibrating portion 1402 and formed thinner than the vibrating portion 1402. Fig.17 The example shown also has a long side parallel to the X-axis and a short side parallel to the Z′ axis, and thin-walled end portions 1404 and 1406 are provided at both ends of the direction in which the long side of the crystal plate 1410 extends. In addition, an excitation electrode 1420 is formed on a first surface 1412, which is one of the principal surfaces of the vibration portion 1402, and an excitation electrode 1430 is formed on a second surface 1414, which is the other principal surface of the vibration portion 1402. The first and second surfaces 1412 and 1414 of the vibration portion 1402 are both formed in a rectangular shape that is long in a direction parallel to the X-axis direction.

[0211] In this modification, the long edge 1420a of the excitation electrode 1420 is parallel to the long edge 1412a of the crystal plate 1410 on the positive Z′ axis side, and when the distance between the long edge 1420a of the excitation electrode 1420 and the long edge 1412a of the crystal plate 1410 is G, and the thickness between the excitation electrodes 1420 and 1430 in the crystal plate 1410 is T, the above-described G / T relationship is obtained. The G / T relationship is also applicable to the relationship between the long edge 1420b of the excitation electrode 1420 on the negative Z′ axis side and the long edge 1412b on the negative X axis side of the crystal plate 1410. The G / T relationship is also applicable to the long side of the crystal plate 1410 on the excitation electrode 1430 side.

[0212] According to this variation, since the crystal piece 1410 has thin-walled end portions 1404 and 1406 at both ends in the long side direction that are thinner than the vibration portion 1402, in addition to being able to obtain good vibration characteristics as already described, it also has the unique effect of a table-type structure with excellent vibration energy sealing.

[0213] Fig.25 1 is a diagram for explaining a crystal resonator element according to a second modification example. In this example, the crystal element includes a crystal piece having a mesa structure in a so-called short-side direction.

[0214] The crystal plate 1510 of the crystal vibrating element 1500 according to this modification includes a vibrating portion 1502 in which an excitation electrode 1520 and an excitation electrode on the negative side of the Y′ axis (not shown) overlap each other, and thin-walled end portions 1504 and 1506 connected to the vibrating portion 1502 and formed thinner than the vibrating portion 1502. Fig.17 The example shown also has a long side parallel to the X-axis and a short side parallel to the Z'-axis, and thin-walled ends 1504 and 1506 are provided at both ends of the direction in which the short side of the crystal plate 1510 extends. In addition, the excitation electrode 1520 is formed on the first surface 1512, which is one of the main surfaces of the vibration part 1502, and the excitation electrode on the negative direction side of the Y'-axis (not shown) is formed on the second surface 1514, which is the other main surface of the vibration part 1502. The first and second surfaces 1512 and 1514 of the vibration part 1502 are both formed in a rectangular shape that is long in a direction parallel to the X-axis direction.

[0215] In this modified example, the long edge 1520a of the excitation electrode 1520 is also parallel to the long edge 1512a of the crystal plate 1510 on the positive side of the Z′ axis, and when the distance between the long edge 1520a of the excitation electrode 1520 and the long edge 1512a of the crystal plate 1510 is G, and the thickness between the excitation electrodes in the crystal plate 1510 is T, the above-described G / T relationship is obtained. The G / T relationship is also applicable to the relationship between the long edge 1520b of the excitation electrode 1520 on the negative side of the Z′ axis and the long edge 1512b on the negative side of the Z′ axis of the crystal plate 1510. The G / T relationship is also applicable to the long side on the excitation electrode 1530 side of the crystal plate 1510.

[0216] According to this variation, since the crystal piece 1510 has thin-walled end portions 1504 and 1506 at both ends in the short side direction that are thinner than the vibration portion 1502, in addition to being able to obtain good vibration characteristics as already described, it also has the unique effects of a table-type structure such as excellent vibration energy sealing.

[0217] In addition, the form of the above-mentioned table structure is not limited to Fig.24 as well as Fig.25 , for example, you can use a combination of Fig.24 as well as Fig.25 The table structure of each structure shown in the figure. According to this, the crystal piece has thin-walled ends in each of the long side direction and the short side direction, and can have Fig.24 as well as Fig.25 The effects of each method described.

[0218] Fig.26This is a diagram for explaining a crystal resonator element according to a third modified example. In this example, a groove is formed between an end portion of a crystal plate and a vibrating portion.

[0219] The crystal plate 1610 of the crystal vibrating element 1600 according to this modification has an excitation electrode 1620 provided on the first surface 1612 and an excitation electrode 1630 provided on the second surface 1614. The first and second excitation electrodes 1620 and 1630 are provided to overlap each other via the crystal plate 1610. The crystal plate 1610 has a vibrating portion 1602 in which the first and second excitation electrodes 1620 and 1630 overlap each other. Fig.17 The example shown also has a long side parallel to the X-axis and a short side parallel to the Z′ axis. In addition, a first end 1604 is provided on the positive X-axis side of the direction in which the long side of the crystal plate 1610 extends, and a second end 1606 is provided on the opposite negative X-axis side. That is, the vibration part 1602 is provided between these first end 1604 and second end 1606.

[0220] Moreover, in Fig.26 In the example shown, grooves 1608 and 1609 are formed between the first end 1604 and the vibration part 1602, and between the second end 1606 and the vibration part 1602, respectively. These grooves 1608 and 1609 extend from one long edge 1612a of the crystal plate 1610 to the other long edge 1612b. Each groove 1608 and 1609 is formed on the Y′ positive direction side of the crystal plate 1610. In addition, as shown in FIG. Fig.26 As shown in FIG. 1 , grooves may also be formed on the Y′ negative direction side of the crystal plate 1610. The depth of the grooves 1608 and 1609 is not particularly limited, and can be appropriately set in a manner to obtain the desired vibration characteristics. The cross-sectional shape perpendicular to the extending direction of the grooves 1608 and 1609 is not particularly limited, and can be as shown in FIG. Fig.26 The concave shape with a bottom surface as shown, or the V-shape formed by two inclined side surfaces. Fig.26 As shown, the grooves 1608 and 1609 can have the same cross-sectional shape in the extension direction, or can have different cross-sectional shapes such as different groove widths.

[0221] The excitation electrode 1620 is formed on the first surface 1612 of the vibration part 1602, and the excitation electrode 1630 is formed on the second surface 1614 of the vibration part 1602. The first and second surfaces 1612 and 1614 of the vibration part 1602 are both formed into a rectangle having a long side parallel to the X axis and a short side parallel to the Z′ axis.

[0222] In this modification, on the positive side of the Z′ axis, the long edge 1620a of the excitation electrode 1620 is parallel to the long edge 1612a on the positive side of the Z′ axis of the crystal plate 1610. When the distance between the long edge 1620a of the excitation electrode 1620 and the long edge 1612a of the crystal plate 1610 is G, and the thickness between the excitation electrodes 1620 and 1630 in the crystal plate 1610 is T, the above-described G / T relationship is obtained. The G / T relationship is also applicable to the relationship between the long edge 1620b of the excitation electrode 1620 on the negative side of the Z′ axis and the long edge 1612b on the negative side of the Z′ axis of the crystal plate 1610. The G / T relationship is also applicable to the long side on the excitation electrode 1630 side of the crystal plate 1610.

[0223] According to this modification, since grooves 1608 and 1609 are formed between the first end 1604 and the vibration part 1602 and between the second end 1606 and the vibration part 1602, respectively, the so-called table-type structure has unique effects. That is, in addition to being able to obtain good vibration characteristics as described above, it also has unique effects of the table-type structure such as excellent vibration energy sealing.

[0224] In addition, Fig.26 In the example shown, for example, a structure in which two rows of grooves are formed on the positive side of the Y' axis is described. However, the shape of the groove is not limited to this, and the groove may be one extending in the direction of the short side of the crystal sheet. Or the grooves extending in the direction of the short side of the crystal sheet may be arranged in more than three rows in the direction of the long side of the crystal sheet. As another method, for example, a wide groove may be formed between the first end and the second end of the crystal sheet, and an excitation electrode may be formed on the bottom surface of the groove. In this case, the bottom surface of the groove in which the excitation electrode is formed becomes the main surface of the vibration portion.

[0225] The structure involved in this embodiment can have the vibration characteristics of the full width thickness shear vibration mode described in the first embodiment. In this case, in addition to the effects described in this embodiment, as described in the first embodiment, uniform vibration can be obtained by generating full width thickness shear vibration. Therefore, good vibration characteristics can be further obtained.

[0226] In the above description, the whole or each structure of the crystal sheet is described as being a substantially rectangular parallelepiped, but the present invention is not limited thereto, and can also be applied to a shape such as an inclined surface structure or a convex surface structure whose thickness gradually decreases from the center toward the end. In this case, the thickness T can be applied to the thickest part between the excitation electrodes (e.g., the center of the excitation electrode).

[0227] In each embodiment, the vibration distribution of the full-width thickness shear vibration mode in the quartz crystal piece is generated on both the front and back sides of the quartz crystal piece.

[0228] The sizes, shapes, directions, etc. of the above-mentioned parts do not need to be strict, and those skilled in the art can understand that they are equivalent.

[0229] In addition, each embodiment described above is an embodiment for facilitating the understanding of the present invention, and is not an embodiment for limiting the interpretation of the present invention. The present invention can be changed / improved without departing from its purport, and its equivalents are also included in the present invention. That is, as long as the features of the present invention are possessed, the embodiments after the technical personnel appropriately add design changes to each embodiment are also included in the scope of the present invention. For example, each element and its configuration, material, condition, shape, size, etc. possessed by each embodiment are not limited to those illustrated and can be appropriately changed. In addition, each element possessed by each embodiment can be combined as long as it is technically feasible, and the embodiment after combining them is included in the scope of the present invention as long as it includes the features of the present invention.

[0230] Explanation of symbols

[0231] 1…Crystal oscillator

[0232] 2…Crystal oscillator

[0233] 10…Crystal Vibration Element

[0234] 11…Crystal

[0235] 14a…Excitation electrode

[0236] 14b…Excitation electrode

[0237] 20…cover parts

[0238] 23…Interior Space

[0239] 30...Substrate

[0240] 36a ...conductive holding member

[0241] 36b ... conductive holding member

[0242] 40…Vibration area

[0243] 50…Non-vibration area

Claims

1. A crystal vibration element, comprising: A crystal piece having a predetermined crystal orientation and having a first direction and a second direction in a plan view; and Excitation electrodes are respectively arranged on the surface and the back of the crystal sheet so as to excite the crystal sheet to undergo thickness shear vibration having a main vibration in the first direction when an alternating electric field is applied. The vibration distribution in the crystal piece with thickness shear vibration as the main vibration comprises a vibration region extending in a band shape in the second direction of the crystal piece, and non-vibration regions adjacent to both sides of the vibration region in the first direction of the crystal piece, The excitation electrodes are provided with gaps of a distance G from both ends of the crystal sheet in the second direction. If the thickness between the excitation electrodes in the crystal sheet is T, then the relationship 0≤G / T≤0.5 is satisfied. The strong vibration region in the vibration region has a first distribution with mutually opposite phases, and the first distribution is located on one side of the surface extending along the first direction and on the other side of the back surface extending along the first direction and spaced from the one side in the second direction. The first distribution has a semi-elliptical distribution formed by longitudinally dividing an ellipse that is longer in the first direction into half, The crystal piece has a trigonal crystal structure which is different from a cubic crystal structure like piezoelectric ceramics.

2. The crystal vibrating element according to claim 1, wherein: The strong vibration region in the vibration region further has a second distribution located on the front surface and the back surface respectively, arranged in the second direction with respect to the first distribution.

3. The crystal vibrating element according to claim 2, wherein: The second distribution is an elliptical distribution that is long in the first direction.

4. The crystal resonator element according to any one of claims 1 to 3, wherein: The strong vibration area of ​​the displacement component in the direction of the normal of the surface in the above-mentioned vibration area, that is, the third direction, also has a third distribution, which is based on the middle line extending along the second direction at the midpoint of the above-mentioned first direction of the above-mentioned crystal piece, and includes a plurality of one distribution located on one side of the above-mentioned middle line in the above-mentioned first direction and arranged along the above-mentioned first direction, and a plurality of another distribution located on the other side of the above-mentioned first direction of the above-mentioned middle line and arranged along the above-mentioned first direction and having opposite phases to the above-mentioned one distribution.

5. The crystal resonator element according to any one of claims 1 to 3, wherein: The excitation electrodes are provided with slits at both ends of the crystal piece in the second direction.

6. The crystal vibrating element according to claim 1, wherein: There is also a relationship of G / T ≤ 0.

2.

7. The crystal vibrating element according to claim 1, wherein: There is also a relationship of 0.0002≤G / T.

8. The crystal vibrating element according to claim 1, wherein: If the width of the crystal piece in the second direction is set to W, the relationship of W / T≤10.2 is satisfied.

9. The crystal resonator element according to any one of claims 1 to 3, wherein: The vibration region is distributed to both ends of the excitation electrode in the second direction reaching the crystal piece.

10. The crystal resonator element according to any one of claims 1 to 3, wherein: The vibration region has one or more strong vibration regions.

11. The crystal resonator element according to any one of claims 1 to 3, wherein: When the crystal piece is viewed from above, it is a rectangle having sides perpendicular to the first direction and the second direction.

12. The crystal resonator element according to any one of claims 1 to 3, wherein: The first direction is the X-axis direction of the crystal orientation of the crystal piece.

13. The crystal resonator element according to any one of claims 1 to 3, wherein: Also available: A frame body surrounding the outer periphery of the crystal piece; and The connecting member connects the crystal piece and the frame.

14. A crystal oscillator, comprising: The crystal vibrating element according to any one of claims 1 to 13; and The crystal sheet is supported as a substrate capable of being excited, The crystal piece is supported on the substrate via a conductive holding member so as to be energizable.

15. The crystal oscillator according to claim 14, wherein: further comprising a cover member bonded to the substrate via a bonding material, The crystal piece is disposed in an internal space between the substrate and the cover member.

16. A crystal oscillator, comprising: The crystal vibrating element according to claim 13; and A first substrate and a second substrate are respectively bonded to the frame body on the front and back sides of the quartz crystal sheet so that the quartz crystal sheet can be housed in the internal space in an energizable manner.

Images