Piezoelectric elements and piezoelectric devices

Abstract

To provide a piezoelectric element capable of reducing energy loss, and a piezoelectric device including the piezoelectric element.SOLUTION: A crystal element 1 includes a crystal blank 3, excitation electrodes 7, extraction electrodes 9, and mounted electrodes 11. The crystal blank 3 expands in a D1 direction and a D2 direction orthogonal to the D1 direction. The two excitation electrodes 7 overlap the front and back of the crystal blank 3, respectively. The two mounted electrodes 11 are located on a -D1 side, and respectively connected to the two excitation electrodes 7 via the respective two extraction electrodes 9. When, in a plane perspective view, an area surrounded by four lines is defined as a first area A1, the four lines comprising a short side 7a on the -D1 side of the excitation electrode 7, two virtual lines extending in parallel in the D1 direction from both ends of the short side 7a on the -D1 side to the -D1 side, and a virtual line in parallel to the D2 direction, the virtual line being in contact from a +D1 side with respect to the two mounted electrodes 11, each extraction electrode 9 extends in a constant width from a long side 7b of each excitation electrode 7 to each mounted electrode 11 without overlapping the first area A1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a piezoelectric element and a piezoelectric device having the piezoelectric element. [Background technology]

[0002] Piezoelectric devices such as quartz crystal resonators and quartz crystal oscillators are known (see, for example, the following patent documents). Such piezoelectric devices include a piezoelectric element such as a quartz crystal element and a package that holds the piezoelectric element.

[0003] A piezoelectric element, for example, has a piezoelectric plate (a plate-shaped piezoelectric body) and two excitation electrodes overlapping the front and back of the piezoelectric plate. When a voltage is applied to the piezoelectric plate by the two excitation electrodes, the piezoelectric plate vibrates. This vibration is used, for example, to generate an oscillation signal (for example, a signal whose signal strength oscillates at a constant frequency).

[0004] The piezoelectric element also has two extraction electrodes extending from the two excitation electrodes toward one end of the piezoelectric plate (for example, one short side of a rectangular piezoelectric plate), and two mounting electrodes located at one end of the piezoelectric plate and connected to the two extraction electrodes. The two mounting electrodes are bonded to two pads on the package, for example, with a conductive bonding material. This electrically connects the piezoelectric element to the package and supports it.

[0005] Patent Document 1 discloses an extraction electrode that extends from the excitation electrode to the mounting electrode via the side of the quartz crystal plate (piezoelectric plate) (the surface connecting the front and back surfaces of the quartz crystal plate). The side of the quartz crystal plate is located to the side of the excitation electrode, and therefore the extraction electrode is located to the side of the region between the excitation electrode and the mounting electrode. In Patent Document 1, the width of the portion of the extraction electrode extending on the side of the quartz crystal plate is wider than the width of the portion extending from the excitation electrode toward the side of the quartz crystal plate on the front and back of the quartz crystal plate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-50751 A Summary of the Invention [Problem to be solved by the invention]

[0007] For example, it is desirable to provide a piezoelectric element and a piezoelectric device that can reduce energy loss. [Means for solving the problem]

[0008] A piezoelectric element according to one aspect of the present disclosure includes a piezoelectric plate extending in a first direction and a second direction perpendicular to the first direction, two excitation electrodes overlapping on the front and back of the piezoelectric plate, two extraction electrodes drawn from the two excitation electrodes, and two mounting electrodes located on a first side in the first direction relative to the two excitation electrodes and connected to the two excitation electrodes via the two extraction electrodes, and each of the two excitation electrodes has a first edge portion located on the first side and extending along the second direction, and a second edge portion extending from both ends of the first edge portion to a second side in the first direction. When a region surrounded by the first edge, two imaginary lines extending parallel to the first direction from both ends of the first edge to the first side, and an imaginary line parallel to the second direction that contacts the two mounting electrodes from the second side is referred to as a first region in a planar perspective view, each of the two extraction electrodes extends with a constant width from one of the two second edges of the excitation electrode corresponding to it of the two excitation electrodes to the mounting electrode corresponding to it of the two mounting electrodes without overlapping the first region.

[0009] A piezoelectric device according to one aspect of the present disclosure includes the piezoelectric element described above and a package that holds the piezoelectric element. [Effects of the Invention]

[0010] According to the above configuration, for example, energy loss can be reduced. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a quartz crystal element according to a first embodiment. [Figure 2] FIG. 2 is another perspective view showing the crystal element of FIG. 1. [Figure 3] FIG. 2 is a plan view of the quartz crystal element of FIG. 1. [Figure 4] An enlarged view of region IV in Figure 3 . [Figure 5] 2 is a cross-sectional view of a quartz crystal device having the quartz crystal element of FIG. 1. [Figure 6] FIG. 10 is a plan view showing a portion of the quartz crystal element according to the second embodiment. [Figure 7] FIG. 10 is a plan view showing a portion of the quartz crystal element according to the third embodiment. [Figure 8] FIG. 10 is a plan view showing a portion of the quartz crystal element according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The drawings used in the following description are schematic. Therefore, for example, the dimensional ratios in the drawings do not necessarily correspond to the actual ones. The dimensional ratios of the same components in the drawings also do not necessarily correspond. In addition, details may be omitted, and some shapes may be exaggerated. However, the above does not deny that the actual dimensional ratios may be as shown in the drawings, or that features such as shapes and dimensional ratios may be extracted from the drawings.

[0013] For convenience, the drawings may include a Cartesian coordinate system D1-D2-D3. In the piezoelectric elements and piezoelectric devices according to the embodiments, any direction may be considered to be the vertical or horizontal direction. However, for convenience, the +D3 side may be expressed as the upper side. Furthermore, unless otherwise specified, a plan view or a plan perspective view refers to a view parallel to the D3 direction. Furthermore, to facilitate understanding of the drawings, hatching may be applied to the surfaces (i.e., surfaces that are not cross-sectional surfaces) of relatively thin layers (e.g., conductor layers).

[0014] In the description of aspects (embodiments and modifications) that will be described later, basically only the differences from the aspects that have been described earlier will be described. Matters that are not specifically mentioned may be considered to be the same as the aspects that have been described earlier, or may be inferred from the aspects that have been described earlier. The description of the aspects that have been described earlier may be used in the aspects that will be described later, unless a contradiction or the like arises. For convenience, corresponding components in multiple aspects may be given the same reference numerals even if there are differences.

[0015] The term "side" as referring to the edge of a planar shape generally refers to the edge of a polygon (in other words, a straight line), but in describing the embodiments, for convenience, it may be used to refer to the edge of a shape that does not have to be a polygon (for example, an edge that may be curved). Similarly, "long side" and "short side" generally refer to the side of a rectangle, but in describing the embodiments, for convenience, it may be used to refer to edges other than rectangles. "Parallel" usually refers to a relationship in which the distance between straight lines is constant, but in describing the embodiments, for convenience, it may be used to refer to a relationship in which the distance between lines that do not have to be straight lines (for example, curved lines) is constant.

[0016] When we say "rectangle" or "rectangular shape," unless otherwise specified, it does not necessarily mean that the shape is a square or a rectangle in the strict sense, but rather that the corners are chamfered. The same applies to polygons other than rectangles. The chamfering here is larger than the roundness of the corners that occurs due to manufacturing errors (tolerances). It goes without saying that tolerances may exist, and are not limited to chamfering.

[0017] First Embodiment (Overview of crystal element) Fig. 1 is a perspective view of a quartz crystal element 1 (an example of a piezoelectric element) according to the first embodiment. Fig. 2 is a perspective view of the quartz crystal element 1 seen from the opposite side to that of Fig. 1. Fig. 3 is a plan view of the quartz crystal element 1.

[0018] The crystal element 1 generates vibrations when, for example, an AC voltage is applied to it. This vibration is used, for example, to generate an oscillation signal in which the signal strength (for example, voltage and / or current) oscillates at a certain frequency. In other words, the crystal element 1 is included in, for example, a crystal resonator or a crystal oscillator. The frequency of the oscillation signal is arbitrary.

[0019] The quartz crystal element 1 has, for example, a quartz crystal plate 3 (an example of a piezoelectric plate) and (at least) two conductor patterns 5 (a first conductor pattern 5A and a second conductor pattern 5B in the illustrated example) overlapping the quartz crystal plate 3. The two conductor patterns 5 are not short-circuited to each other. Each conductor pattern 5 has, for example, an excitation electrode 7, an extraction electrode 9 leading from the excitation electrode 7, and a mounting electrode 11 connected to the extraction electrode 9. In other words, the quartz crystal element 1 has a pair of excitation electrodes 7, a pair of extraction electrodes 9, and a pair of mounting electrodes 11.

[0020] The pair of mounting electrodes 11 contributes to the mounting of the crystal element 1. Specifically, for example, as shown in Fig. 5 described later, the mounting electrodes 11 and the package 103 are bonded together by a conductive bonding material 105. This electrically connects and fixes the crystal element 1 to the package 103.

[0021] The crystal element 1 may be mounted on a member (for example, a circuit board) other than the package 103. However, for the sake of convenience, the description of the embodiment may be given on the assumption that it is mounted on the package 103.

[0022] When an AC voltage is applied to the pair of mounting electrodes 11 via the package 103, the AC voltage is applied to the pair of excitation electrodes 7 via the pair of extraction electrodes 9. As a result, an AC voltage (electric field) is applied to the quartz crystal substrate 3 by the pair of excitation electrodes 7, causing the quartz crystal substrate 3 to vibrate.

[0023] In Fig. 3, an area located between two excitation electrodes 7 (one of which is not shown in Fig. 3) and two mounting electrodes 11 in a planar perspective view and having the same width as each excitation electrode 7 (length in the D2 direction) is surrounded by a dashed line. This area will be referred to as the first area A1. The extraction electrode 9 extends with a constant width from the excitation electrodes 7 to the mounting electrodes 11 without overlapping with the first area A1.

[0024] The configuration of the extraction electrode 9 as described in the previous paragraph reduces energy loss, for example. The details will be described later, but one example of this is that it avoids the phenomenon of current reflection occurring in the portion where the width of the extraction electrode 9 changes.

[0025] The above is an overview of the quartz crystal element 1 according to the first embodiment. The first embodiment will be described below in the following order: Note that the first region A1 is a region in the quartz crystal substrate 3 (Section 2), but since its range is defined by the excitation electrode 7 and the mounting electrode 11, it will be described in the description of the conductor pattern 5 (Section 3). 1. General matters concerning crystal elements 1 2. Crystal base plate 3 3. Conductive pattern 5 3.1.Excitation electrode 7 3.2. Mounted electrode 11 3.3.First area A1 3.4.Extraction electrode 9 4. Examples of crystal element dimensions 5. Example of use of crystal element 1 (Figure 5) 6. Summary of the First Embodiment

[0026] (1. Matters relating to crystal elements in general) As described above, in this embodiment, the two extraction electrodes 9 extend with a constant width, avoiding the first region A1. This configuration may be applied to various types of quartz crystal elements 1. Various types of quartz crystal elements 1 have, for example, at least the following components: a quartz crystal substrate 3 (in other words, a plate-shaped quartz crystal piece); two excitation electrodes 7 overlapping and facing each other on the front and back of the quartz crystal substrate 3; two extraction electrodes 9 extending from the two excitation electrodes 7; and two mounting electrodes 11 connected to the two extraction electrodes 9.

[0027] Regarding the quartz crystal plate 3, a plate shape is, for example, a shape whose length (thickness) in a predetermined direction (D3 direction) is sufficiently short compared to the length along a plane perpendicular to the predetermined direction (direction along the D1-D2 plane). The determination of whether a shape is plate-shaped based on thickness and other lengths may be made reasonably. Examples of dimensions that qualify as plate-shaped will be described later (see Section 4). The front and back surfaces of the plate-shaped quartz crystal plate 3 (the surfaces where the two excitation electrodes 7 overlap) are the widest surfaces of the plate shape, and in the description of this embodiment, they may be referred to as the main surfaces, or the first surface 3a and second surface 3b.

[0028] The quartz crystal substrate 3 extends in a first direction (D1 direction) and a second direction (D2 direction) perpendicular to the first direction. In a planar perspective view, the two mounting electrodes 11 are located on one side of the two excitation electrodes 7 in the D1 direction (the -D1 side; from another perspective, on the side of the first end 3c). This allows the definition of a first region A1 located between the two excitation electrodes 7 and the two mounting electrodes 11 in the quartz crystal substrate 3. In addition, a configuration can be applied in which the extraction electrode 9 extends with a constant width, avoiding the first region A1.

[0029] The quartz crystal element 1 is, for example, a so-called AT-cut quartz crystal element. In an AT-cut quartz crystal element, so-called thickness-shear vibration occurs when an AC voltage is applied to the quartz crystal plate 3 by a pair of excitation electrodes 7. The quartz crystal element 1 may utilize vibrations other than thickness-shear vibration. Examples of vibrations other than thickness-shear vibration include bending vibration mode, torsional vibration mode, length-extensional vibration mode, width-extensional vibration mode, width-length-extension combined vibration mode, and contour-shear vibration mode. Furthermore, the quartz crystal element 1 utilizing thickness-shear vibration may have a cut angle other than AT-cut. For example, the quartz crystal element 1 may be a BT-cut quartz crystal element.

[0030] In the description of this embodiment, for convenience, the description and expressions may be given on the assumption that the crystal element 1 is of the AT-cut type unless otherwise specified.

[0031] As will be described in detail later, the quartz crystal element 1 is mounted so as to face the bottom surface (first substrate surface 111c) of the recess R1 of the package 103 (see FIG. 5). The quartz crystal element 1 may be configured so that either the +D3 side surface (first surface 3a) or the -D3 side surface (second surface 3b) faces the first substrate surface 111c, or may not be configured that way (the illustrated example). For example, the quartz crystal element 1 may be configured so as to be 180° rotationally symmetric about an unillustrated axis of symmetry (center line) parallel to the D1 direction, or may not be configured that way (the illustrated example). In the description of this embodiment, a configuration will be basically taken as an example in which, of the first surface 3a and the second surface 3b, the second surface 3b is assumed to be the surface facing the first substrate surface 111c.

[0032] The quartz crystal element 1 may be fabricated by various methods. For example, the quartz crystal plate 3 may be fabricated by etching (e.g., wet etching).

[0033] The quartz crystal blank 3 produced by etching may have inclined surfaces (or, from another perspective, crystal planes) on the side surfaces, etc., due to the anisotropy of quartz crystal with respect to etching. In the description of the embodiments, the existence of such inclined surfaces is generally ignored. When strictness is required in the description of dimensions, etc., the description may be applied ignoring the inclined surfaces, or may be applied taking the inclined surfaces into account, as long as it does not lack rationality or cause contradictions. For example, when referring to the length of the quartz crystal blank 3 in the D1 direction, this length may be the length of the first surface 3a or the second surface 3b (the length excluding the crystal planes), or it may be the maximum length in a planar perspective (the length taking the crystal planes into account).

[0034] (2. Crystal base plate) As can be understood from the above explanation, the cut angle of the quartz crystal substrate 3 is arbitrary. In an AT-cut quartz crystal substrate 3, for example, the X axis of the crystal is parallel to the D1 direction, the Y' axis of the crystal is parallel to the D3 direction, and the Z' axis of the crystal is parallel to the D2 direction. The Y' axis and Z' axis are typically obtained by rotating the Y axis and Z axis by 35°15' around the X axis. 35°15' may also be 35°15'±10°. Thickness-shear vibration is vibration that moves the first surface 3a and the second surface 3b relative to each other in the D1 direction (X-axis direction). The positive side of the D1 direction and the positive side of the X axis may be the same side or opposite sides. The same applies to the relationship between the positive and negative sides of other directions and the positive and negative sides of other axes.

[0035] The specific shape of the quartz crystal plate 3 may be various. In the illustrated example, the quartz crystal plate 3 is flat. That is, the first surface 3a and the second surface 3b are planar and parallel to each other. From another perspective, the thickness of the quartz crystal plate 3 is constant.

[0036] The crystal substrate 3 may have a shape other than a flat plate. Examples of such shapes include: a so-called mesa type, in which the central region (mesa portion) that overlaps with the pair of excitation electrodes 7 and is excited is thicker than the peripheral region; an inverted mesa type, in which the central region (inverted mesa portion) that overlaps with the pair of excitation electrodes 7 and is excited is thinner than the peripheral region; a crystal substrate having a vibrating portion that overlaps with the pair of excitation electrodes 7 and is excited, and a fixed portion that is thicker than the vibrating portion and is adjacent to part of the edge of the vibrating portion (e.g., one, two, or three sides), and on which a pair of mounting electrodes 11 are located; a bevel type, in which the peripheral portion becomes thinner as it approaches the outer edge. In the crystal substrate having the above vibrating portion and fixed portion, the fixed portion may be thicker on one side (e.g., the -D3 side) of the vibrating portion, or thicker on both sides (the -D3 side and the +D3 side).

[0037] In the illustrated example, the planar shape of the quartz crystal plate 3 is rectangular. That is, the quartz crystal plate 3 has a pair of parallel sides and another pair of parallel sides. The former pair of sides and the latter pair of sides are perpendicular to each other. From another perspective, the planar shape of the quartz crystal plate 3 has a pair of opposing edges (not necessarily straight lines) and another pair of opposing edges (not necessarily straight lines). The former pair of edges and the latter pair of edges intersect each other (not necessarily perpendicular to each other). In other words, the planar shape of the quartz crystal plate 3 is a shape whose outline can be considered to be composed of four edges.

[0038] The planar shape of the quartz crystal plate 3 may be a shape other than a rectangle. Examples of such shapes include a circle, an ellipse, or a polygon other than a rectangle. The planar shape of the quartz crystal plate 3 may also be a polygonal shape with any number of sides (for example, one, two, three, or four sides of a rectangle) bulging outward in a curved manner. The planar shape of the quartz crystal plate 3 may also be a shape with a protrusion or notch in part. Note that a rectangular shape with any number of sides bulging outward in a curved manner is an example of a planar shape of the quartz crystal plate 3 that can be considered to be composed of four edges.

[0039] The planar shape of the quartz crystal substrate 3 may have either the D1 direction or the D2 direction as its longitudinal direction, or may have a shape in which such a distinction cannot be made (for example, a square or circular shape). As mentioned above, the D1 direction is the direction from the two excitation electrodes 7 to the two mounting electrodes 11, and from another perspective, it is the direction of thickness-shear vibration. When the planar shape of the AT-cut quartz crystal substrate 3 allows distinction between the longitudinal direction and the lateral direction, the D1 direction is often the longitudinal direction (this may also be the case in this embodiment). However, in the example shown in Figures 1 to 3, the direction perpendicular to the thickness-shear vibration direction (the D2 direction) is the longitudinal direction.

[0040] The shape of the quartz crystal plate 3 may be symmetrical (as shown in the example), or may not be symmetrical. Examples of the latter include a quartz crystal plate having a vibrating portion and a fixed portion as described above, in which the fixed portion is thicker only on one side (the -D3 side) of the vibrating portion, and a quartz crystal plate in which the fixed portion is located along two or three sides of the vibrating portion in a plan view (an L-shaped or U-shaped fixed portion).

[0041] Unlike the illustrated example, the quartz crystal plate 3 may have recesses, protrusions, and through-holes at appropriate positions for various purposes. Such recesses, protrusions, and / or through-holes may be located in the first region A1. The recesses, protrusions, and / or through-holes located in the first region A1 may, for example, contribute to reducing the effect that the fixing of the mounting electrode 11 to the package 103 has on vibrations in the region of the excitation electrode 7. Furthermore, the through-holes may, for example, contribute to electrical conduction between the front and back surfaces of the conductor pattern 5.

[0042] (3. Conductive Pattern) The material of the conductive pattern 5 may be, for example, a metal. Examples of the metal include nickel (Ni), chromium (Cr), titanium (Ti), gold (Au), or silver (Ag), or an alloy containing at least one of these as a main component. The conductive pattern 5 may be composed of a single conductive layer made of a single material, or may be composed of a plurality of laminated conductive layers made of different materials. The conductive pattern 5 may have the same material composition over its entire area, or may have different material composition in different regions.

[0043] The thickness of the conductive pattern 5 is basically constant throughout. Therefore, for example, in the extraction electrode 9, the area of ​​the cross section (a cross section perpendicular to the extension direction) is proportional to the width in a planar view. Also, for example, in the extraction electrode 9, if the width is constant, the resistance value per unit length is constant. However, the thickness of some regions of the conductive pattern 5 may be different from the thickness of other regions. For example, in a configuration in which the quartz crystal substrate has a surface parallel to the D1-D2 plane and a surface inclined to the D1-D2 plane, and the conductive pattern 5 (e.g., the extraction electrode 9) overlaps both of these surfaces, the thickness of the portion overlapping the former surface may be different from the thickness of the portion overlapping the latter surface.

[0044] (3.1. Excitation electrode) As described above, the pair of excitation electrodes 7 are located on both main surfaces (first surface 3a and second surface 3b) of the quartz crystal plate 3 to apply a voltage to the quartz crystal plate 3. The pair of excitation electrodes 7 are provided, for example, in positions, shapes, and sizes that allow them to overlap each other roughly equally in a planar perspective. However, it is acceptable for there to be portions that do not overlap each other. The position, shape, size, etc. of the excitation electrodes 7 in a planar view may be set as appropriate.

[0045] For example, the excitation electrode 7 is located in a central region of the quartz crystal plate 3. From another perspective, the excitation electrode 7 is located away from the outer edge of the quartz crystal plate 3. For example, the geometric center of the excitation electrode 7 roughly coincides with the geometric center of the quartz crystal plate 3 in a planar view in the D2 direction. Furthermore, the geometric center of the excitation electrode 7 is located, for example, on the +D1 side (the opposite side from the two mounting electrodes 11) of the geometric center of the quartz crystal plate 3.

[0046] In the illustrated example, the shape of the excitation electrode 7 (planar shape unless otherwise specified) is rectangular. For example, the excitation electrode 7 has a pair of short sides 7a that are parallel to each other and a pair of long sides 7b that are parallel to each other. The pair of short sides 7a and the pair of long sides 7b are perpendicular to each other. From another perspective, the shape of the excitation electrode 7 has a pair of edges (not necessarily straight lines) that face each other and another pair of edges (not necessarily straight lines) that face each other. The former pair of edges and the latter pair of edges intersect each other (not necessarily perpendicular to each other). In other words, the shape of the excitation electrode 7 can be considered as having a contour that is composed of four edges.

[0047] The excitation electrode 7 may have various shapes having a first edge (short side 7a on the -D1 side) on the mounting electrode 11 side and two second edges (two long sides 7b) extending from both ends of the first edge to the opposite side of the mounting electrode 11. For example, one, two (e.g., one pair of short sides or one pair of long sides), three, or four of the four sides of the excitation electrode 7 may bulge outward in a curved manner. Furthermore, for example, the boundary between the edge (short side 7a on the +D1 side) on the opposite side of the mounting electrode 11 and the two second edges (two long sides 7b) may not be clear. For example, the +D1 side of the excitation electrode 7 may be semi-elliptical.

[0048] The excitation electrodes 7 may have either the D1 direction or the D2 direction as their longitudinal direction, or may not have such a distinction (for example, a square shape). As mentioned above, the D1 direction is the direction from the two excitation electrodes 7 to the two mounting electrodes 11, and from another perspective, it is the direction of thickness-shear vibration. When the excitation electrodes 7 of the AT-cut crystal element 1 have a distinction between the longitudinal direction and the lateral direction, the D1 direction is often the longitudinal direction. In the illustrated example, the excitation electrodes 7 also have the D1 direction as their longitudinal direction. That is, the maximum length (or average length) in the D1 direction is longer than the maximum length (or average length) in the D2 direction.

[0049] In plan view, the shape of the excitation electrode 7 and the shape of the quartz crystal plate 3 may be similar or different. An example of the former is when both the shape of the quartz crystal plate 3 and the shape of the excitation electrode 7 are rectangular. An example of the latter is when one of the shape of the quartz crystal plate 3 and the shape of the excitation electrode 7 is rectangular, and the other has one, two, three, or four sides that curve outward.

[0050] (3.2. Mounted electrodes) As described above, the two mounting electrodes 11 are located on one side (-D1 side, the side of the first end 3c) in the first direction (D1 direction) relative to the two excitation electrodes 7. Note that, in this case, the two excitation electrodes 7 and the two mounting electrodes 11 may partially overlap each other in the arrangement range in the D2 direction perpendicular to the D1 direction (as in the illustrated example), or may not overlap each other. Because both of the two mounting electrodes 11 are located on the -D1 side, when the two mounting electrodes 11 are fixed to the package 103 by the bonding material 105, the crystal element 1 is supported in a cantilevered manner (see FIG. 5).

[0051] The two mounting electrodes 11 are aligned along the first end 3c (the edge on the -D1 side of the quartz crystal plate 3). The two mounting electrodes 11 may be provided, for example, with positions, shapes, and sizes that are approximately symmetrical with respect to a center line (not shown) parallel to the D1 direction of the quartz crystal plate 3. However, the two mounting electrodes 11 may be asymmetrical in position, shape, and / or size. For example, the two mounting electrodes 11 may differ from each other in the position and / or area of ​​the intermediate portion 11c described below.

[0052] Each mounting electrode 11 can be considered to have, for example, the following three portions: an upper surface portion 11a that overlaps the first surface 3a of the quartz crystal plate 3; a lower surface portion 11b that overlaps the second surface 3b of the quartz crystal plate 3; and an intermediate portion 11c that overlaps the side surface of the quartz crystal plate 3 and connects the upper surface portion 11a and the lower surface portion 11b. As mentioned above, the second surface 3b is the surface that faces the first substrate surface 111c of the package 103. Therefore, the lower surface portion 11b is the portion that faces the first substrate surface 111c.

[0053] When viewed from above, the positions, shapes, and sizes of the upper surface portion 11a and the lower surface portion 11b may be different from each other (as in the illustrated example) or may be the same. From another perspective, as described above, when the crystal element 1 is mounted in the package 103, the surface facing the first substrate surface 111c may be limited to one of the first surface 3a and the second surface 3b (here, the second surface 3b) (as in the illustrated example), or may not be limited to this. In the former embodiment, the mounting electrode 11 may have only the lower surface portion 11b, or only the lower surface portion 11b and the intermediate portion 11c.

[0054] The specific position, shape and size of each of the above-mentioned parts may be set as appropriate. In the illustrated example, they are as follows.

[0055] The upper surface portion 11a and the lower surface portion 11b are each rectangular. From another perspective, the upper surface portion 11a and the lower surface portion 11b each have two edges that coincide with the edge on the -D1 side of the first surface 3a and the second surface 3b and an edge (the edge on the -D2 side or the +D2 side) that is connected to the edge. Furthermore, the upper surface portion 11a and the lower surface portion 11b each have one edge that is along (for example, parallel to) the short side 7a (edge) of the excitation electrode 7 on the mounting electrode 11 side.

[0056] In the illustrated example, the longitudinal direction of each of the upper surface portion 11a and the lower surface portion 11b is the D2 direction (a direction perpendicular to the direction from the two excitation electrodes 7 to the two mounting electrodes 11). The ratio of the length (e.g., maximum length) in the longitudinal direction (D2 direction) to the length (e.g., maximum length) in the lateral direction (D1 direction) is larger than that of a typical mounting electrode 11. For example, the longitudinal length may be two or more times, three or more times, or five or more times the lateral length.

[0057] In the illustrated example, the area of ​​the lower surface portion 11b is larger than the area of ​​the upper surface portion 11a. The length of the lower surface portion 11b in the D1 direction is longer than the length of the upper surface portion 11a in the D1 direction. The length of the lower surface portion 11b in the D2 direction may be shorter (in the illustrated example) than the length of the upper surface portion 11a in the D2 direction, or it may be the same as or longer than the length of the upper surface portion 11a in the D2 direction.

[0058] In the illustrated example, the middle portion 11c is located on the -D1 side of the quartz crystal plate 3, and is also located on the -D2 or +D2 side of the quartz crystal plate 3. The portion located on the -D1 side of the quartz crystal plate 3 extends over the entire D3 direction of the side, and also extends over at least the shorter of the D2 direction length of the upper surface 11a and the D2 direction length of the lower surface 11b (the longer length in the illustrated example). The portion located on the -D2 or +D2 side of the quartz crystal plate 3 extends over the entire D3 direction of the side, and also extends over at least the shorter of the D1 direction length of the upper surface 11a and the D1 direction length of the lower surface 11b (the longer length in the illustrated example).

[0059] The positions, shapes, and sizes of the components of the mounting electrode 11 may differ from those shown in the drawings. For example, the lower surface 11b and / or the upper surface 11a may be other than rectangular (e.g., circular, elliptical, or polygonal). The edges of the lower surface 11b and / or the upper surface 11a on the excitation electrode 7 side may not be parallel to the edge of the excitation electrode 7 on the mounting electrode 11 side (the short side 7a on the -D1 side), and may not necessarily be aligned with the short side 7a. The length of the lower surface 11b and / or the upper surface 11a in the D1 direction may be equal to or greater than the length in the D2 direction. The middle portion 11c may be located on only one of the side surfaces on the -D1 side and the side surface on the -D2 side or +D2 side. The middle portion 11c of one mounting electrode 11 may be separated in a direction along the outer edge of the quartz crystal plate 3 in a plan view, and may have two or more portions. The length in the D2 direction of the portion of the intermediate portion 11c located on the side surface on the -D1 side may be shorter than the length in the D2 direction of the lower surface portion 11b and the length in the D2 direction of the upper surface portion 11a. The same applies to the length in the D1 direction of the portion located on the side surface on the -D2 side or the +D2 side.

[0060] (3.3.First area) Up to now, the first region A1 has been described as a region that is located between the two excitation electrodes 7 and the two mounting electrodes 11 in a planar perspective view and has the same width as the width (length in the D2 direction) of each excitation electrode 7. Here, the first region A1 will be described from a different perspective or expression so that the first region A1 can be clearly identified (defined) even in an embodiment in which the positions, shapes, and dimensions of the excitation electrodes 7 and mounting electrodes 11 are different from those in the illustrated example.

[0061] As described above, the quartz crystal plate 3 can be considered to extend in a first direction (direction D1 in the illustrated example) and a second direction (direction D2 in the illustrated example) perpendicular to the first direction. The first direction is the direction from the two excitation electrodes 7 to the two mounting electrodes 11. More specifically, the first direction may be a direction parallel to an axis of symmetry (not shown) when, for example, the shape of the quartz crystal plate 3 (and / or the excited regions of the quartz crystal plate 3) is made symmetrical or when the shapes of the two mounting electrodes 11 are made symmetrical.

[0062] The two mounting electrodes 11 are located on the first side in the first direction (one side in the first direction; in the illustrated example, the -D1 side; from another perspective, the side of the first end 3c) relative to the two excitation electrodes 7. As already mentioned, the arrangement range of the two excitation electrodes 7 in the second direction (D2 direction) and the arrangement range of the two mounting electrodes 11 in the second direction may or may not overlap. The side opposite to the first side in the first direction (the other side in the second direction; in the illustrated example, the +D1 side) can be referred to as the second side.

[0063] The boundary line of the first region A1 on the excitation electrode 7 side (+D1 side) may be the first edge portion (the short side 7a on the -D1 side in the illustrated example) on the first side (-D1 side) of the excitation electrode 7. Therefore, for example, in a mode in which the short side 7a on the -D1 side is curved so as to bulge outward (towards the -D1 side), the first region A1 has a shape in which both side portions in the D2 direction are wider towards the +D1 side than the central portion in the D2 direction.

[0064] In many cases, the two excitation electrodes 7 are basically assumed to overlap each other exactly in planar perspective. Therefore, either of the first edge portions of the two excitation electrodes 7 may be used to define the first region A1. In a mode in which the positions of the two first edge portions in the first direction are partially or entirely misaligned, the portion of the two first edge portions that is relatively located on the first side (which may be the entirety of one of the first edge portions) may be regarded as part of the boundary line of the first region A1. In other words, the boundary line of the first region A1 may be defined so as to narrow the first region A1 toward the first side.

[0065] The boundary lines on both sides of the first region A1 in the second direction (D2 direction) may be virtual lines (reference numerals omitted; in other words, virtual straight lines) extending parallel to the first direction (D1 direction) from both ends of the first edge portion (the short side 7a on the -D1 side) to the first side (the -D1 side). Therefore, for example, in an embodiment in which the two long sides 7b are curved and bulge outward (to both sides in the D2 direction), the width (length in the D2 direction) of the first region A1 is smaller than the maximum width of the excitation electrode 7.

[0066] As described above, basically, either first edge portion (short side 7a on the -D1 side) of the two excitation electrodes 7 may be used to identify the first region A1. Note that, if the positions of the +D2 side ends of the two first edges in the D2 direction are different from each other, the position on the -D2 side relatively may be used to identify the position of the +D2 side boundary line of the first region A1 in the D2 direction. Similarly, if the positions of the -D2 side ends of the two first edges in the D2 direction are different from each other, the position on the +D2 side relatively may be used to identify the position of the -D2 side boundary line of the first region A1 in the D2 direction. That is, the boundary line of the first region A1 may be identified so as to reduce the width (length in the D2 direction) of the first region A1.

[0067] The corner between the first edge (short side 7a on the -D1 side) and the second edge (long side 7b) may be chamfered. In this case, the end of the first edge may be identified by imagining the shape without chamfering. For example, if the first edge and / or the second edge are straight, the straight line may be extended. If the first edge and / or the second edge are curved, the curve may be extended so as to maintain the curvature (or the curvature of the end if the curvature is not constant). This may identify a virtual intersection between the first edge and the second edge when chamfering is not performed, and the intersection may be used as the end of the first edge. Then, using the first edge virtually extended to the identified end, the boundary line on the second side (+D1 side) and the boundary lines on both sides in the second direction (-D2 side and +D2 side) of the first region A1 may be identified.

[0068] The boundary line of the first side (-D1 side) of the first region A1 may be an imaginary line (reference numeral omitted; in other words, an imaginary straight line) that contacts the two mounting electrodes 11 from the second side (+D1) in a planar perspective view and is parallel to the second direction (D2 direction). Therefore, for example, even if the +D1-side edge of the mounting electrodes 11 is curved and bulges toward the +D1 side, the boundary line of the -D1 side of the first region A1 is a straight line. Furthermore, this -D1-side boundary line is located closer to the excitation electrode 7 (second side) than the entire mounting electrode 11, except for the point (or line) where the boundary line contacts the +D1-side edge of the mounting electrodes 11.

[0069] The requirement that the boundary line (virtual line) on the first side (-D1 side) of the first region A1 contact the two mounting electrodes 11 does not mean that it must contact both of the two mounting electrodes 11, but rather that it must contact the single component when the two mounting electrodes 11 are viewed as a single component. Therefore, for example, in a configuration in which the +D1-side edge of one mounting electrode 11 is located closer to the +D1 side than the +D1-side edge of the other mounting electrode 11, the virtual line only needs to contact the +D1-side edge of the one mounting electrode 11. However, since a pair of mounting electrodes 11 are typically configured symmetrically with respect to an axis of symmetry (e.g., the center line of the quartz crystal plate 3) parallel to the first direction (D1 direction), the virtual line will contact both mounting electrodes 11.

[0070] Furthermore, the boundary line (imaginary line) on the first side (-D1 side) of the first region A1 is in contact with the two mounting electrodes 11 in a planar perspective view. Therefore, in an embodiment in which the positions of the +D1-side edges in the D1 direction differ between the upper surface portion 11a and the lower surface portion 11b, as in the illustrated example, the +D1-side edge located relatively closer to the +D1 side may be used to identify the boundary line. For example, in the illustrated example, the +D1-side edge of the lower surface portion 11b may be used to identify the boundary line.

[0071] In summary, the first region A1 may be an area surrounded, in planar perspective, by the first edge (short side 7a on the -D1 side) of (at least one) excitation electrode 7, two imaginary lines extending parallel to the first direction (D1 direction) from both ends of the first edge to the first side (-D1 side), and an imaginary line parallel to the second direction (D2 direction) that contacts the two mounting electrodes 11 from the second side (+D1 side).

[0072] Note that, when specifying the first region A1, specific portions of the excitation electrode 7 and the mounting electrode 11 may be excluded. For example, if the mounting electrode 11 has a relatively small protrusion protruding toward the +D1 side on part of its edge on the +D1 side in planar perspective view (for example, a protrusion whose protrusion amount and width are both smaller than the width of the extraction electrode 9), such a protrusion may be ignored. Defining the first region A1 while ignoring such a protrusion does not necessarily contradict the spirit of the technology according to the present disclosure.

[0073] (3.4. Extraction electrode) As described above, each extraction electrode 9 extends with a constant width from one of the two second edges (long sides 7b in the illustrated example) of the corresponding excitation electrode 7 to the corresponding mounting electrode 11 without overlapping the first region A1. As long as this requirement is met, the specific position, shape, and dimensions of the extraction electrode 9 are arbitrary. In the illustrated example, the extraction electrode 9 extends linearly from the second edge (long sides 7b) of the excitation electrode 7 to the edge on the second side (+D1 side) of the mounting electrode 11 in a direction inclined at an angle θ1 to the first direction (D1 direction).

[0074] As described above, the boundary line of the first region A1 on the excitation electrode 7 side (+D1 side) may be the first edge portion (short side 7a on the -D1 side) of the first side of the excitation electrode 7. Therefore, the extraction electrode 9 that satisfies the requirement of not overlapping the first region A1 does not have a portion extending from the short side 7a within its width. For example, the extraction electrode 9 extends from the second edge portion (long side 7b) with respect to its entire width. Of course, there may be a portion extending from the short side 7a due to manufacturing errors (tolerances).

[0075] In the previous explanation of the first region A1, it was stated that when the corner between the first edge (short side 7a on the -D1 side) and the second edge (long side 7b) is chamfered, the end of the first edge may be identified by imagining the intersection of the first edge and the second edge when they are not chamfered. The extraction electrode 9 that does not overlap with the first region A1 identified using the first edge extended to the above-mentioned imaginary end may be considered to extend only from the second edge, and not from the first edge.

[0076] FIG. 4 is an enlarged view of region IV in FIG.

[0077] As described above, the extraction electrode 9 extends with a constant width from the excitation electrode 7 to the mounting electrode 11. However, the width of the connection portion 9a of the extraction electrode 9 with the excitation electrode 7 may not be constant depending on the shape of the edge (more specifically, the second edge) of the excitation electrode 7 and / or the orientation of the extraction electrode 9 with respect to the edge of the excitation electrode 7, although this depends on how the width is defined.

[0078] For example, in the example of Fig. 4, the extraction electrode 9 basically extends linearly with a constant width. However, since the direction in which the long side 7b of the excitation electrode 7 extends and the direction in which the extraction electrode 9 extends are not perpendicular to each other, a triangular region (region with diagonal hatching) is formed in the connection portion 9a. When the length of this triangular region is considered to be the width in the direction perpendicular to the direction in which most of the extraction electrode 9 extends (the direction inclined at an angle θ1 with respect to the D1 direction), for example, it cannot be said that the width of this triangular region is constant. It is acceptable for such a region to exist.

[0079] Therefore, when it is said that the extraction electrode 9 extends with a constant width from the excitation electrode 7 to the mounting electrode 11, the extraction electrode 9 only needs to have a constant width in the range inclined at an angle θ1 in the D1 direction, for example, from the mounting electrode 11 side to the position where at least one of the two edges 9c and 9d on both sides of the width of the extraction electrode 9 (edge ​​9c in the illustrated example) is connected to the excitation electrode 7 (long side 7b).

[0080] 4, the extraction electrode 9, which extends with a constant width to the end of the excitation electrode 7 side as shown by the dashed line within the excitation electrode 7, can also be considered to overlap with a part (a triangular area shown by the dashed line) of the excitation electrode 7. In this way, the extraction electrode 9 may be considered to extend with a constant width even at the connection portion 9a.

[0081] 4, the long side 7b is straight and parallel to the first direction (direction D1), but it is clear that the above explanation may also be applied when the long side 7b is not straight (for example, when it is curved) and / or when it is inclined in the direction D1. Furthermore, it goes without saying that the extraction electrode 9 may extend with a constant width even at the connection portion 9a by, for example, orthogonally intersecting the second edge portion (long side 7b) with the extraction electrode 9 (see FIG. 8 described later).

[0082] The connection portion 9a of the extraction electrode 9 with the excitation electrode 7 has been described above, but the same applies to the connection portion 9b of the extraction electrode 9 with the mount electrode 11. That is, the width of the connection portion 9b does not have to be constant. In other words, when the extraction electrode 9 extends with a constant width from the excitation electrode 7 to the mount electrode 11, the extraction electrode 9 only needs to have a constant width in a range inclined at an angle θ1 toward the D1 direction, for example, from the excitation electrode 7 side to a position where at least one edge portion (edge ​​9c in the illustrated example) of the two edges 9c and 9d on both sides of the extraction electrode 9 in the width direction is connected to the mount electrode 11 (more specifically, the edge on the +D1 side in the illustrated example). Furthermore, the extraction electrode 9 extending with a constant width to the end on the mount electrode 11 side and the mount electrode 11 may be considered to partially overlap each other.

[0083] As mentioned above, the +D2 or -D2 side of the quartz crystal substrate 3 may have an inclined surface that is inclined with respect to the D3 direction. The mount electrode 11 may have a portion located on the inclined surface. Furthermore, the connection portion 9b of the extraction electrode 9 with the mount electrode 11 may also have a portion located on the inclined surface. The shape of such a unique portion may be such that it is difficult to recognize that the extraction electrode 9, which extends with a constant width to the end on the mount electrode 11 side, and the mount electrode 11 partially overlap. Even in this case, for example, as described above, if the width of the extraction electrode 9 is constant from the excitation electrode 7 side to the position where at least one of the two edges 9c and 9d (edge ​​9c in the illustrated example) is connected to the mount electrode 11, the requirement that the width from the excitation electrode 7 to the mount electrode 11 be constant can be interpreted as being satisfied.

[0084] As mentioned above, the quartz crystal substrate 3 is not limited to a flat plate shape (as shown in the example). For example, the quartz crystal substrate 3 may have an inclined surface that gradually changes its thickness. The extraction electrode 9 may have a portion located on such an inclined surface. In the portion of the extraction electrode 9 on the inclined surface, the width of the extraction electrode 9 when viewed parallel to the D3 direction differs from the width of the extraction electrode 9 when viewed normal to the inclined surface. In such a case, the width of the portion of the extraction electrode 9 on the inclined surface may be used to determine whether the width of the extraction electrode 9 is the same as the width of the other region. Ideally, the width and thickness of the extraction electrode 9 when viewed normal to each surface are the same across multiple surfaces. This is because the resistance per unit length is constant. However, this may be difficult to achieve due to design and manufacturing constraints. Therefore, for example, the extraction electrode 9 may have a constant width when viewed from a planar perspective (when viewed parallel to the D3 direction).

[0085] Furthermore, in a configuration in which the quartz crystal substrate 3 has a mesa portion or an inverted mesa portion, the edge of the excitation electrode 7 may be located on a slope surrounding the mesa portion or the inverted mesa portion. As a result, the connection portion 9a of the extraction electrode 9 with the excitation electrode 7 may have a unique portion located on a relatively steep slope. The shape of such a unique portion may be such that it is difficult to perceive the extraction electrode 9, which extends with a constant width to the end on the excitation electrode 7 side, as partially overlapping with the excitation electrode 7. Even in this case, for example, as described above, if the width of the extraction electrode 9 is constant in the range from the mounting electrode 11 side to the position where at least one of the two edges 9c and 9d (edge ​​9c in the illustrated example) is connected to the excitation electrode 7, the requirement that the width from the excitation electrode 7 to the mounting electrode 11 be constant may be interpreted as being satisfied.

[0086] The connection position of the extraction electrode 9 to the second edge (long side 7b) of the excitation electrode 7 is arbitrary. For example, the edge 9c on the first side (-D1 side) of the extraction electrode 9 may be connected to the first-side end of the second edge (as in the illustrated example), or may be spaced apart from the first-side end of the second edge to the second side (+D1 side). In the latter case, the distance between the edge 9c and the first-side end of the second edge is also arbitrary. For example, this distance may be shorter, equal to, or longer than the length (length in the D1 direction) along the second edge of the portion where the extraction electrode 9 and the second edge are connected.

[0087] The connection position of the extraction electrode 9 to the mount electrode 11 is also arbitrary. In the illustrated example, the extraction electrode 9 is connected to the edge of the second side (+D1 side) of the mount electrode 11. More specifically, as shown in FIGS. 1, 3, and 4, the extraction electrode 9 on the upper surface side (+D3 side) is connected to the edge of the upper surface portion 11a of the corresponding mount electrode 11 on the +D1 side. Furthermore, as shown in FIGS. 2 and 3, the extraction electrode 9 on the lower surface side (-D3 side) is connected to the edge of the lower surface portion 11b of the corresponding mount electrode 11 on the +D1 side. From another perspective, each extraction electrode 9 (part or all (all in the illustrated example) of its width) is connected to the mount electrode 11 on the first surface 3a or the second surface 3b.

[0088] Other connection positions of the extraction electrode 9 to the mount electrode 11 include, for example, the following. The extraction electrode 9 may be connected to another edge of the mount electrode 11 in addition to or instead of the edge of the second side (+D1) of the mount electrode 11. As described above, the mount electrode 11 may not have the upper surface portion 11a, but may have only the middle portion 11c and the lower surface portion 11b. In this case, the extraction electrode 9 on the upper surface side (+D3 side) may be connected to, for example, the edge on the upper surface of the middle portion 11c. Furthermore, as described above, the mount electrode 11 may not have the upper surface portion 11a and the middle portion 11c, but may have only the lower surface portion 11b. In this case, the extraction electrode 9 on the upper surface side (+D3 side) may be connected to an edge at any position on the lower surface portion 11b via the side surface of the quartz crystal plate 3. Whether the portion of the conductive pattern 5 located on the side surface of the quartz crystal plate 3 is part of the extraction electrode 9 or the middle portion 11c of the mounting electrode 11 can be reasonably determined based on its shape, etc.

[0089] The extraction electrode 9 (part or all of its width) may be connected to the edge of the second side (+D1 side) of the mounting electrode 11 on the side of the quartz crystal plate 3. In this case, the side of the quartz crystal plate 3 may be parallel to the D3 direction, or may be partially or completely inclined relative to the D3 direction. In the latter embodiment, the side of the quartz crystal plate 3 may have a crystal plane (e.g., an m-plane) that appears due to the anisotropy of quartz crystal with respect to etching. The extraction electrode 9 may be connected to the mounting electrode 11 across its entire width within a single crystal plane. As mentioned above, in the description of the embodiments, unless otherwise specified, the existence of inclined surfaces is ignored, and the description in the following paragraphs will be limited to the first surface 3a or the second surface 3b.

[0090] In the illustrated example, extraction electrode 9 is connected to the edge on the +D3 side of mount electrode 11, and the specific position thereof is also arbitrary. As shown in Figures 1, 3, and 4, in the illustrated example, extraction electrode 9 on the upper surface side (+D3 side) has second-side (+D1 side) edge 9d connected to the end of the +D1 side edge of upper surface portion 11a on the -D2 side (the side on which the corresponding mount electrode 11 is located in the arrangement direction of the two mount electrodes 11). Also, as can be seen from Figures 2 and 3, extraction electrode 9 on the lower surface side (-D3 side) has a 180-degree rotationally symmetric relationship with extraction electrode 9 on the upper surface side with respect to a center line (not shown) parallel to the D1 direction. The lower surface side extraction electrode 9 has its second side (+D1 side) edge 9d connected to a position slightly away from the +D2 side end of the +D1 side edge of the lower surface portion 11b (the side on which the corresponding mounting electrode 11 is located in the arrangement direction of the two mounting electrodes 11).

[0091] Of course, unlike the illustrated example, the two extraction electrodes 9 do not necessarily have a 180° rotationally symmetric relationship. The edge 9d of the extraction electrode 9 on the upper surface side (+D3 side) may be spaced apart from the -D2 side end of the +D1 side edge of the upper surface portion 11a. The edge 9d of the extraction electrode 9 on the lower surface side (-D3 side) may be connected to the +D2 side end of the +D1 side edge of the lower surface portion 11b. The distance between the edge 9d of the extraction electrode 9 on the +D3 side or the -D3 side and the edge of the +D1 side of the upper surface 11a or the lower surface 11b is arbitrary.

[0092] (4. Example of crystal element dimensions) Below are examples of dimensions of each part of the quartz crystal element 1. Note that these dimensional examples may be applied to the embodiments described below unless otherwise specified. Conversely, the range of dimensions exemplified here may include dimensions that cannot be applied to the quartz crystal element 1 according to this embodiment.

[0093] Furthermore, for example, the length in the D1 direction of the quartz crystal blank 3 is not constant in an embodiment in which the edges on the +D1 side and / or the -D1 side of the quartz crystal blank 3 are curved. In such an embodiment in which the predetermined dimension is not constant, the dimensions exemplified below may apply to any of the maximum dimension, minimum dimension, or average dimension unless otherwise specified. Irregular parts (for example, relatively small protrusions on the quartz crystal blank 3) may or may not be taken into account when measuring the dimensions exemplified below.

[0094] The various dimensional ranges may be appropriately combined without causing any contradictions. For example, the upper limit of the range of the D1 direction length of the excitation electrode 7 is shown as a value greater than the lower limit of the range of the D1 direction length of the quartz crystal plate 3. However, the range of the D1 direction length of the excitation electrode 7 and the range of the D1 direction length of the quartz crystal plate 3 may be combined, provided that the D1 direction length of the excitation electrode 7 does not exceed the D1 direction length of the quartz crystal plate 3. The condition for not causing any contradictions is logically clear, and will not be specifically explained below.

[0095] The length of the quartz crystal substrate 3 (or, from another perspective, the quartz crystal element 1) in the first direction (D1 direction) may be 500 μm or more and 1500 μm or less. The length of the quartz crystal substrate 3 in the second direction (D2 direction) may be 300 μm or more and 2000 μm or less. The thickness of the quartz crystal substrate 3 (the thickness between a pair of excitation electrodes 7) may be 3 μm or more and 100 μm or less.

[0096] In a quartz crystal element 1 that utilizes thickness-shear vibration, the thickness between a pair of excitation electrodes 7 of the quartz crystal substrate 3 is a factor that determines the frequency of the oscillation signal. For example, as is well known, in an AT-cut quartz crystal element, the relationship f = 1.67 × n / t basically holds. Here, f is the frequency (MHz), n is the order of vibration used, and t (mm) is the thickness. The quartz crystal element 1 may utilize either the fundamental mode or the overtone mode. Since the fundamental mode may be used and the thickness t may be 3 μm or more and 100 μm or less, the frequency used by the quartz crystal element 1 may be, for example, 16 MHz or more and 500 MHz or less.

[0097] The length of the excitation electrode 7 in the first direction (D1 direction) may be 200 μm or more and 1200 μm or less. The range of the length of the excitation electrode 7 in the second direction (D2 direction) may be the same as above. When the length of the excitation electrode 7 in the first direction is longer than the length in the second direction, the former may be 1.1 times or more and 1.5 times or less than the latter.

[0098] The length of the quartz crystal plate 3 in the first direction (D1 direction) may be 1.1 to 2 times the length of the excitation electrode 7 in the first direction. The length of the quartz crystal plate 3 in the second direction (D2 direction) may be 1.1 to 3 times the length of the excitation electrode 7 in the second direction.

[0099] The distance in the first direction (D1 direction) from the edge on the second side of the excitation electrode 7 (short side 7a on the +D1 side) to the edge on the second side of the quartz crystal plate 3 may be 50 μm or more and 300 μm or less. In addition, this distance may be 1 / 20 or more and 1 / 3 or less of the length of the excitation electrode 7 in the first direction.

[0100] The distance d1 (see FIG. 4) in the second direction (D2 direction) from the edge (long side 7b on the +D2 side or the -D2 side) of the excitation electrode 7 to the edge of the quartz crystal plate 3 in the second direction may be 50 μm or more and 800 μm or less. Furthermore, the distance d1 may be 1 / 20 or more and 1 time or less the width (length in the second direction) of the excitation electrode 7.

[0101] The distance d2 in the first direction (direction D1) between the excitation electrode 7 and the mounting electrode 11 (from another perspective, the length of the first region A1 in the first direction; see FIG. 4) may be 50 μm or more and 300 μm or less. Moreover, this distance may be 1 / 20 or more and 1 / 3 or less of the length of the excitation electrode 7 in the first direction.

[0102] If the distance d2 is 50 μm or more, 80 μm or more, or 100 μm or more, the likelihood that the bonding material 105 will reach the excitation electrode 7 is reduced. Also, if the distance d2 is equal to or more than the lower limit as described above, the influence of fixation by the bonding material 105 on excitation by the excitation electrode 7 is likely to be reduced in a mode in which the frequency used by the crystal element 1 is 100 MHz or more.

[0103] The distance d3 in the first direction (D1 direction) between the first region A1 and the edge of the first side (-D1 side) of the quartz crystal plate 3 (or, from another perspective, the length of the mounting electrode 11 in the first direction; see FIG. 4) may be 50 μm or more and 300 μm or less. Furthermore, this distance may be 1 / 20 or more and 1 / 3 or less of the length of the excitation electrode 7 in the first direction.

[0104] The angle θ1 of the direction in which the linear extraction electrodes 9 extend relative to the first direction (D1 direction) may be 0° or more, 10° or more, 20° or more, 30° or more, or 40° or more, or may be 60° or less, 50° or less, 45° or less, 40° or less, or 35° or less. The above lower and upper limits may be arbitrarily combined so as not to cause a contradiction. For example, the angle θ1 may be 30° or more and 45° or less.

[0105] The width of the extraction electrode 9 (the length in the direction perpendicular to the extension direction of the extraction electrode 9) may be 20 μm or more, 50 μm or more, or 100 μm or more, or 300 μm or less, 200 μm or less, or 100 μm or less. The above lower and upper limits may be arbitrarily combined so as not to cause any contradiction. The width of the extraction electrode 9 may be 1 / 10 to 1 / 3 of the width of the excitation electrode 7 (the length in the D2 direction).

[0106] In this embodiment, the extraction electrode 9 extends linearly from the second edge (long side 7b) of the excitation electrode 7 in a direction inclined at an angle θ1 toward the first direction (direction D1) to reach the mounting electrode 11. In this embodiment, in order for the extraction electrode 9 to reach the mounting electrode 11 on the main surface (first surface 3a or second surface 3b) of the quartz crystal plate 3, the distance d1 must be at least d2 × tan θ1. That is, the lower limit of the range of the distance d1 may be d2 × tan θ1. Even when the lower limit of the range of the distance d1 is d2 × tan θ1, the above-described range of the distance d1 (50 μm to 800 μm and / or 1 / 20 to 1 times the width of the excitation electrode 7) may be applied.

[0107] In this embodiment, the lower limit of the range of the distance d1 may be relatively large, which facilitates realizing the extraction electrode 9 that extends linearly from the excitation electrode 7 to the mounting electrode 11 on the main surface of the quartz crystal plate 3 while avoiding the first region A1. For example, the lower limit of the distance d1 may be set to 100 μm or 200 μm, or may be set to 1 / 3 or 1 / 2 of the width of the excitation electrode 7.

[0108] (5. Examples of using crystal elements) 5 is a cross-sectional view of a quartz crystal device 101 as an example of use of the quartz crystal element 1. This figure corresponds to line VV in FIG.

[0109] The crystal device 101 is, for example, an electronic component having a generally thin rectangular parallelepiped shape as a whole. The dimensions of the crystal device may be any appropriate size. For example, the length of the long or short side is 0.6 mm or more and 2.0 mm or less, and the thickness in the vertical direction is 0.2 mm or more and 1.5 mm or less. The crystal device 101 is surface-mounted, for example, with its bottom surface facing the top surface of a mounting substrate (e.g., a circuit board) (not shown).

[0110] The crystal device 101 is configured as, for example, a crystal resonator. The crystal device 101 includes, for example, a crystal element 1 and a package 103 that holds the crystal element 1. The package 103, for example, contributes to protecting the crystal element 1 and contributing to electrical connection between the crystal element 1 and the mounting substrate (not shown).

[0111] The package 103 includes, for example, a base 107 that supports the crystal element 1, and a lid 109 that is bonded to the base 107 and hermetically seals the crystal element 1. The internal space of the package 103 is, for example, evacuated or filled with an appropriate gas (for example, nitrogen). The base 107 includes, for example, an insulating member 111 and various conductors located in the insulating member 111.

[0112] The insulating member 111 has a recess R1 that accommodates the crystal element 1. From another perspective, the insulating member 111 has a flat substrate portion 111a and a frame portion 111b that is provided along the edge of the upper surface of the substrate portion 111a. The substrate portion 111a and the frame portion 111b may be made of any material, such as ceramic. The substrate portion 111a has a first substrate surface 111c that forms the bottom surface of the recess R1 and a second substrate surface 111d that forms the lower surface of the crystal device 101.

[0113] Examples of conductors that the base 107 has include: Two pads 113 (only one is shown) that are electrically connected to the crystal element 1; Four external terminals 115 (only two are shown) for mounting the crystal device 101 on the mounting base; Two wiring conductors 117 (only one is shown) that connect the two pads 113 to two of the four external terminals 115. An AC voltage is applied to the crystal element 1 by applying an AC voltage to the two external terminals 115 that are connected to the two pads 113 via the two wiring conductors 117.

[0114] The two pads 113 are bonded to the two extraction electrodes 9 by two bonding materials 105. This fixes the crystal element 1 and electrically connects the two excitation electrodes 7 to the two external terminals 115. In other words, the crystal element 1 is mounted in the package 103. The two pads 113 are formed of a conductor layer (e.g., metal) that overlaps the first substrate surface 111c. As can be seen from the positions of the two mounting electrodes 11, the two pads 113 are aligned in the short direction (D2 direction) of the substrate portion 111a at one end side (-D1 side) of the longitudinal direction of the substrate portion 111a. The shape and dimensions of the pads 113 are arbitrary.

[0115] The four external terminals 115 are formed by a conductor layer (e.g., metal) that overlaps the second substrate surface 111d. The positions, shapes, and dimensions of the external terminals 115 are arbitrary. For example, the four external terminals 115 are located at the four corners of the second substrate surface 111d. The positions of the two external terminals 115 connected to the two pads 113 are also arbitrary. For example, the two external terminals 115 may be located at a pair of diagonal corners of the second substrate surface 111d, or at two corners on the -D1 side.

[0116] The two wiring conductors 117 may have various configurations. For example, the wiring conductor 117 may have a via conductor penetrating the substrate portion 111a, or may have a layered conductor overlapping the first substrate surface 111c, the second substrate surface 111d, the inside of the substrate portion 111a, and / or the side surface of the substrate portion 111a (including the inner surface of the castellation), or may have both a via conductor and a layered conductor. Note that the wiring conductor 117 illustrated in FIG. 5 is composed only of a via conductor.

[0117] The bonding material 105 may be made of any material. For example, the bonding material 105 may be made of a conductive adhesive. The conductive adhesive is made of a thermosetting resin mixed with a metal filler. The bonding material 105 may be bonded to only the lower surface portion 11b of the mounting electrode 11, or may be bonded to the lower surface portion 11b and also to the middle portion 11c (as shown in the example), or may be bonded to the upper surface portion 11a.

[0118] Just to be clear, bonding material 105 is not bonded to, for example, portions of conductor pattern 5 other than mounting electrode 11 (extraction electrode 9 and excitation electrode 7), nor is it bonded to areas of the principal surfaces (first surface 3a and second surface 3b) of quartz crystal substrate 3 that are exposed from conductor pattern 5. However, bonding material 105 may extend outward from mounting electrode 11 in a relatively small amount, as long as the amount does not significantly reduce the characteristics, and may be bonded to a portion of extraction electrode 9 on the mounting electrode 11 side.

[0119] The lid 109 is, for example, a flat plate-like member made of an insulator or a metal. The method of joining the lid 109 to the base 107 is also arbitrary. For example, the two may be joined by seam welding. In the illustrated example, metal layers 119 and 121 used for seam welding are shown. In an embodiment in which the lid 109 is made of metal, one or two of the two external terminals 115 that are not connected to the two pads 113 may be connected to the lid 109 via wiring conductors 117 (not shown).

[0120] The quartz crystal element 1 may be used in various ways in addition to the above-mentioned examples of use.

[0121] For example, a quartz crystal resonator (piezoelectric resonator) may have electronic elements other than the quartz crystal element 1. Examples of such electronic elements include a temperature-sensitive element (e.g., a thermistor). Furthermore, the quartz crystal device (piezoelectric device) may be a quartz crystal oscillator (piezoelectric oscillator) that includes, in addition to the quartz crystal element 1, an integrated circuit element (IC) that applies a voltage to the quartz crystal element 1 to generate an oscillation signal.

[0122] As can be seen from the above, the number of pads and external terminals that a crystal device has is arbitrary, and the roles and connection relationships of the multiple pads and multiple external terminals are also arbitrary. For example, in an oscillator, the two pads 113 on which the crystal element 1 is mounted may be electrically connected to an IC within the oscillator, rather than to the external terminals 115.

[0123] In the piezoelectric device, the structure of the package that packages the crystal element 1 may be configured appropriately. For example, the package may have an H-shaped cross section with recesses on the top and bottom surfaces. In this case, for example, the above-mentioned temperature-sensing element or IC may be mounted in the recess on the bottom surface. The package may also be configured with a substrate-like base (a base without a recess) and a cap-like lid that is placed over the base. For example, the piezoelectric device (package) may also have a thermostatic oven.

[0124] (6. Summary of the First Embodiment) As described above, the piezoelectric element (quartz crystal element 1) according to this embodiment has a piezoelectric substrate (quartz crystal substrate 3), two excitation electrodes 7, two extraction electrodes 9, and two mounting electrodes 11. The quartz crystal substrate 3 extends in a first direction (D1 direction) and a second direction (D2 direction) perpendicular to the D1 direction. The two excitation electrodes 7 overlap on the front and back of the quartz crystal substrate 3. The two extraction electrodes 9 are extracted from the two excitation electrodes 7. The two mounting electrodes 11 are located on the first side (-D1 side) of the two excitation electrodes 7 in the D1 direction, and are connected to the two excitation electrodes 7 via the two extraction electrodes 9. Each of the two excitation electrodes 7 has a first edge portion (short side 7a on the -D1 side) located on the -D1 side and extending along the D2 direction, and two second edge portions (long sides 7b) extending from both ends of the first edge portion to a second side (+D2 side) in the D1 direction.

[0125] Here, the area surrounded by the following edges and imaginary lines in a planar perspective view is referred to as the first area A1: the short side 7a on the -D1 side; two imaginary lines (reference numerals omitted) extending parallel to the D1 direction from both ends of the short side 7a on the -D1 side toward the -D1 side; and imaginary lines parallel to the D2 direction that contact the two mount electrodes 11 from the +D1 side. When the first area A1 is defined in this way, each of the two extraction electrodes 9 extends with a constant width from one of the two long sides 7b of the corresponding one of the two excitation electrodes 7 to the corresponding one of the two mount electrodes 11 without overlapping the first area A1.

[0126] Therefore, compared to, for example, an embodiment in which the extraction electrode 9 is located in the first region A1, conductors other than the excitation electrode 7 (extraction electrode 9 and mounting electrode 11) are not concentrated in the region (including the first region A1) extending from the excitation electrode 7 to the edge of the quartz crystal plate 3 on the -D1 side by the width of the excitation electrode 7. This reduces the likelihood that vibrations in the excitation electrode 7 region and its surrounding region will differ from the intended vibrations due to the influence of conductors other than the excitation electrode 7, for example, when the quartz crystal element 1 is miniaturized and the distance between the excitation electrode 7 and the mounting electrode 11 is shortened. In particular, in an AT-cut type that uses thickness-shear vibration in which the first surface 3a and the second surface 3b move relative to each other in the D1 direction, the fact that the extraction electrode 9 does not overlap the first region A1 makes it easier to reduce the influence of the extraction electrode 9 on vibrations. From another perspective, in this embodiment, it is easier to miniaturize the quartz crystal element 1 compared to an embodiment in which the extraction electrode 9 is located in the first region A1.

[0127] Here, as a result of intensive studies by the inventors of the present disclosure, it was found that even if the influence of the extraction electrode 9 on vibration is reduced by arranging the extraction electrode 9 so that it does not overlap with the first region A1, there may be cases where the expected improvement in electrical characteristics is not necessarily confirmed. Furthermore, when the cause of this is investigated, it was found that, as a result of arranging the extraction electrode 9 so that it does not overlap with the first region A1, the shape of the extraction electrode 9 becomes more complex compared to a general configuration (a configuration in which the extraction electrode 9 extends parallel to the D1 direction from the short side 7a on the -D1 side of the excitation electrode 7 to the mounting electrode 11), and the extraction electrode 9 directly affects the electrical characteristics.

[0128] On the other hand, in this embodiment, the width of the extraction electrode 9 is constant from the excitation electrode 7 to the mounting electrode 11. Therefore, for example, reflection of current (or, from another perspective, electrical signal) is reduced in the portion where the width of the extraction electrode 9 changes. As a result, energy loss is reduced, and the degradation of electrical characteristics caused by the extraction electrode 9 itself, as described in the previous paragraph, is reduced. This effect is particularly effective when the crystal element 1 is miniaturized, the width of the extraction electrode 9 is reduced, and the resistance value of the extraction electrode 9 is relatively high.

[0129] The quartz crystal substrate 3 may have two main surfaces (first surface 3a and second surface 3b) located on the front and back sides, and side surfaces connecting the two main surfaces. One of the two extraction electrodes 9 (the extraction electrode 9 on the +D3 side) may be connected (by at least a portion of its width) to one of the two mount electrodes 11 on one of the two main surfaces (first surface 3a). The other of the two extraction electrodes 9 (the extraction electrode 9 on the -D3 side) may be connected (by at least a portion of its width) to the other of the two mount electrodes 11 on the other of the two main surfaces (second surface 3b).

[0130] In this case, compared to a configuration in which the extraction electrode 9 extends from the excitation electrode 7 to the side surface of the quartz crystal plate 3 and is connected to the mounting electrode 11 only at that side surface (this configuration may also be included in the technology disclosed herein), the extraction electrode 9 has a reduced or eliminated portion that extends across the boundary between the main surface (first surface 3a or second surface 3b) and the side surface. As a result, for example, the extraction electrode 9 has fewer three-dimensionally curved portions. This reduces the likelihood of current reflection and / or electromagnetic waves occurring due to bending. Furthermore, the reduced curved portions reduce the likelihood of changes in the thickness of the extraction electrode 9, which in turn reduces the likelihood of current reflection due to thickness changes. The reduced reflection of electromagnetic waves and / or current reduces energy loss. Furthermore, the width of the extraction electrode 9 is less likely to be affected, for example, by changes in the thickness of the quartz crystal plate 3 depending on the target frequency or by changes in the shape of the side surface (crystal plane) of the quartz crystal plate 3 due to changes in manufacturing method conditions. As a result, it is easy to make the width of the extraction electrode 9 constant.

[0131] Each of the two extraction electrodes 9 may extend linearly from the corresponding excitation electrode 7 to the corresponding mounting electrode 11 in a direction inclined with respect to the D1 direction.

[0132] In this case, the effect of reducing energy loss is improved. The reason for this is that in an embodiment where the extraction electrode 9 has a curved portion (see FIG. 6 described later), there is a possibility that electrical signals will be reflected at the curved portion, but when the extraction electrode 9 is straight, this probability is low. Also, although electromagnetic waves may be generated at the curved portion, this probability is also low. In other words, EMI (Electromagnetic Interference) is reduced. Furthermore, when the dimensions of the quartz crystal substrate 3 and excitation electrodes 7, etc. are fixed (when the dimensions of the quartz crystal substrate 3, etc. are not changed depending on the shape of the extraction electrode 9), the length of the extraction electrode 9 is minimized. From this perspective as well, energy loss is reduced.

[0133] The inclination angle (angle θ1) of each of the linear extraction electrodes 9 with respect to the direction D1 may be set to be equal to or greater than 30° and equal to or less than 45°.

[0134] When the angle θ1 is 30° or more, for example, it is easy to separate the extraction electrode 9 from the first region A1. As a result, the effect of reducing the influence of the extraction electrode 9 on vibration described above is improved. Furthermore, when the angle θ1 is 45° or less, for example, it is easy to reduce the distance d1 (>d2×tan θ1) from the long side 7b of the excitation electrode 7 to the edge of the quartz crystal plate 3. This is advantageous for miniaturizing the quartz crystal element 1 in the D2 direction.

[0135] The minimum value of each of the distances d2 from the two long sides 7b of the excitation electrode 7 to the two edges of the quartz crystal substrate 3 located on both sides of the two long sides 7b in the D2 direction may be greater than or equal to half the maximum value of the width of each of the two excitation electrodes 7 in the D2 direction.

[0136] In this case, it is easy to extend the extraction electrode 9 in a straight line, diagonally relative to the D1 direction, from the long side 7b of the excitation electrode 7 to the mounting electrode 11. In a typical quartz crystal element 1, such a wide area is not secured to the side (-D2 side or +D2 side) of the excitation electrode 7. In particular, when the quartz crystal substrate 3 is flat, such a wide area is not secured.

[0137] Furthermore, the piezoelectric device (crystal device 101) according to this embodiment includes the crystal element 1 as described above and a package 103 that holds the crystal element 1. This allows for the crystal device 101 to be realized with reduced energy loss, for example.

[0138] Second Embodiment Fig. 6 is a plan view showing a portion of the quartz crystal element 201 according to the second embodiment. This figure corresponds to Fig. 4 of the first embodiment. In this figure, for the sake of convenience, different regions of the extraction electrode 209 are hatched differently.

[0139] In the second embodiment, the extraction electrode 209 also extends with a constant width from the long side 7b of the excitation electrode 7 to the mounting electrode 11 without overlapping the first region A1. However, while the extraction electrode 9 in the first embodiment extends linearly, the extraction electrode 209 in this embodiment has a bent portion 209f that bends toward the first side (-D1 side) in the first direction. This makes it easier to reduce the distance d1 compared to the first embodiment, for example. Just to be sure, other extraction electrodes 209 (and the distance d1 associated with the other extraction electrodes 209) not shown in FIG. 6 are also similar to the illustrated extraction electrode 209 (180-degree rotational symmetry).

[0140] More specifically, in the illustrated example, the extraction electrode 209 has a connection portion 209a (e.g., the area hatched with diagonal lines) connected to the excitation electrode 7, a first straight portion 209e extending linearly from the connection portion 209a, the above-mentioned curved portion 209f (e.g., the area hatched with diagonal lines) connected to the first straight portion 209e, and a second straight portion 209g extending linearly from the curved portion 209f to the mounting electrode 11.

[0141] The connection portion 209a and the first straight portion 209e correspond to a part of the extraction electrode 9 of the first embodiment on the excitation electrode 7 side. The connection portion 209a does not have to have a constant width, similar to the connection portion 9a of the first embodiment, although this depends on how the width is defined. The first straight portion 209e extends linearly in a direction inclined at an angle θ1 with respect to the D1 direction, similar to the extraction electrode 9 of the first embodiment. The length of the first straight portion 209e is arbitrary. For example, the length may be shorter (in the illustrated example), equal to, or longer than the width of the extraction electrode 209, and may also be shorter (in the illustrated example), equal to, or longer than the length of the second straight portion 209g.

[0142] The second straight portion 209g extends parallel to the D1 direction. In other words, the angle of the extension direction of the second straight portion 209g with respect to the D1 direction is 0°. Unlike the example shown in the figure, the second straight portion 209g may be inclined with respect to the D1 direction toward a side away from the first region A1 as it approaches the mounting electrode 11 (i.e., toward the same side as the inclined side of the corresponding first straight portion 209e). In this case, the angle of the second straight portion 209g with respect to the D1 direction is smaller than the angle θ1. Also, unlike the above, the second straight portion 209g may be inclined with respect to the D1 direction toward a side closer to the first region A1 as it approaches the mounting electrode 11. However, in this case, the angle of the second straight portion 209g with respect to the D1 direction is set so that the extraction electrode 209 does not overlap the first region A1. As can be understood from the above, when the extraction electrode 209 is said to be bent toward the -D1 side, the angle of the direction after the bend (the direction in which the second straight portion 209g extends) relative to the D1 direction is not limited to 0° (in the example shown), but may be an angle whose positive and negative sign are the same as those of the angle θ1 but whose absolute value is smaller, or an angle whose positive and negative sign are different from those of the angle θ1.

[0143] The length of the second straight portion 209g (the length in the direction in which the second straight portion 209g extends) is arbitrary. For example, the length of the second straight portion 209g in the direction D1 (which is the same as the length in the direction in which the second straight portion 209g extends in the illustrated example) may be less than half, approximately half, or more than half the length of the first region A1 in the direction D1 (distance d2) (in the illustrated example).

[0144] The extraction electrode 209 also has a constant width at the connection portion (reference numeral omitted; included in the second linear portion 209g) with the mounting electrode 11. However, as described in the first embodiment, the width may not be constant due to the shape of the mounting electrode 11 and / or the direction of connection between the extraction electrode 209 and the mounting electrode 11. For example, in a mode in which the second linear portion 209g is inclined at an angle smaller than angle θ1 (but not 0°) with respect to the D1 direction, a triangular region (region with a variable width) may be formed by the connection portion, as in the first embodiment.

[0145] The shape of the curved portion 209f may be various. In the illustrated example, the curved portion 209f is a fan-shaped region. Note that the fan-shaped region and its surrounding region may also be considered as the curved portion 209f. In the illustrated example, the curved portion 209f has an arc-shaped (or, in a broader sense, curved) edge 209j on the outer periphery side, with a bending point P1 as its center. The bending point P1 is the intersection of two straight edge portions 209h and 209i. In other words, the bending point P1 is the end of the edge 209h of the first straight portion 209e located on the inner periphery side of the curved portion 209f, which is on the curved portion 209f side, and is also the end of the edge 209i of the second straight portion 209g located on the inner periphery side of the curved portion 209f, which is on the curved portion 209f side. The magnitude of the central angle of the arc-shaped edge portion 209j (fan-shaped region) is, for example, the same as the difference between the angle θ1 of the first straight portion 209e (edge ​​portion 209h) relative to the D1 direction and the inclination angle (symbol omitted; 0° in the illustrated example) of the second straight portion 209g (edge ​​portion 209i) relative to the D1 direction, and is the same as the angle θ1 in the illustrated example.

[0146] Although not specifically shown, the width of the extraction electrode 209 at various positions in the direction in which the extraction electrode 209 extends in the curved portion may be defined, for example, by the length of the extraction electrode 209 in a direction perpendicular to the tangents at various positions on the outer circumferential edge of the curved portion. In the curved portion 209f (fan-shaped region) in the illustrated example, the direction perpendicular to the tangents at various positions on the edge 209j is the radial direction of the arc-shaped edge 209j, and the width of the extraction electrode 209 is constant because it is the radius of the arc formed by the edge 209j. In other words, the width of the extraction electrode 209 is constant at the curved portion 209f. Consequently, the width of the extraction electrode 209 is constant throughout the first straight portion 209e, the curved portion 209f, and the second straight portion 209g.

[0147] Examples of curved portions different from the illustrated examples include the following: An embodiment in which the inner edge and outer edge are arc-shaped with the same center and central angle but different radii An embodiment in which the inner edge and outer edge are curved with a variable curvature (in other words, not arc-shaped), and the width of the extraction electrode 209 defined in the previous paragraph is constant.

[0148] As described above, in this embodiment, each of the two extraction electrodes 209 extends with a constant width from one of the two second edge portions (long sides 7b) of the excitation electrode 7 corresponding to it among the two excitation electrodes 7 to the mounting electrode 11 corresponding to it among the two mounting electrodes 11 without overlapping with the first region A1.

[0149] Therefore, the same effects as those of the first embodiment can be achieved. For example, the influence of the extraction electrode 209 on vibration can be reduced, and energy loss in the extraction electrode 209 can be reduced.

[0150] Each of the two extraction electrodes 209 may have a bending portion 209f that bends toward the first side (-D1 side) while extending from the corresponding excitation electrode 7 to the corresponding mounting electrode 11. An edge 209j on the outer periphery of the bending portion 209f may be curved.

[0151] In this case, for example, by making at least the outer peripheral edge 209j curved, the extension direction of the extraction electrode 209 can be changed while maintaining a constant width of the extraction electrode 209. Furthermore, by changing the extension direction of the extraction electrode 209, as described above, it becomes easier to shorten the distance d1 compared to the first embodiment. Consequently, it becomes easier to miniaturize the crystal element 201.

[0152] Each of the two extraction electrodes 209 may have a straight portion (second straight portion 209g) that extends linearly from the bent portion 209f toward the first side (-D1 side). The edge portion 209j on the outer periphery side of the bent portion 209f may have an arc-shaped portion centered on the end portion (bending point P1) of the edge portion 209i, of the two edges of the second straight portion 209g, that is located on the inner periphery side of the bent portion 209f.

[0153] From another perspective, each of the two extraction electrodes 209 may have an edge portion located on the inner periphery side of the bent portion 209f that extends linearly and has two portions (209h and 209i) that intersect with each other at the bending point P1. The edge portion 209j on the outer periphery side of the bent portion 209f may be arc-shaped with the bending point P1 as its center.

[0154] In these cases, the extraction electrode 209 can make a large change in direction in a small space compared to other embodiments in which, for example, both the inner and outer peripheral edges are arc-shaped, thereby improving the effect of shortening the distance d1.

[0155] Third Embodiment 7 is a plan view showing a part of a quartz crystal element 301 according to the third embodiment. This figure corresponds to a part of FIG. 4 of the first embodiment.

[0156] In the first embodiment, it was described that the width of the connection portion 9a of the extraction electrode 9 with the excitation electrode 7 does not have to be constant, although this depends on the definition of width. However, the connection portion 9a may have a constant width. The third embodiment is such an example. Specifically, the connection portion 309a of the extraction electrode 309 with the excitation electrode 7 in the third embodiment has a configuration similar to the curved portion 209f in the second embodiment. That is, the outer edge of the connection portion 309a is arc-shaped with the point P2 as the center. This makes the width of the connection portion 309a constant.

[0157] In the illustrated example, the extraction electrode 309 extends linearly in a direction inclined with respect to the first direction (direction D1) from the position where at least a part of its width is connected to the excitation electrode 7 (the position of point P2) to the mounting electrode 11 (not shown here). Therefore, the extraction electrode 309 may be regarded as an example of an extraction electrode that extends linearly in a direction inclined with respect to the first direction (direction D1) from the excitation electrode 7 to the mounting electrode 11, similar to the extraction electrode 9 of the first embodiment.

[0158] Furthermore, the extraction electrode 309 has a configuration (connection portion 309a) similar to the bending portion 209f of the second embodiment. Therefore, like the extraction electrode 209 of the second embodiment, the extraction electrode 309 may be regarded as an example of an extraction electrode having a bending portion (connection portion 309a) that bends toward the first side (-D1 side) while extending from the corresponding excitation electrode 7 to the corresponding mounting electrode 11.

[0159] In the third embodiment, point P2 is different from bending point P1 in the second embodiment in that it is not an intersection of two linear edges of the extraction electrode 209, but an intersection of a second edge (long side 7b) of the excitation electrode 7 and an edge on the -D1 side (inner circumference side of the bent portion from another perspective) of the extraction electrode 309. More specifically, in the illustrated example, point P2 is located at the end of the long side 7b on the -D1 side. Note that, unlike the illustrated example, point P2 (the intersection of the long side 7b and the edge on the -D1 side of the extraction electrode 309) may be spaced away from the end of the long side 7b on the +D1 side.

[0160] When focusing on the straight portion closer to the mounting electrode 11 than the bent portion (connection portion 309a), point P2 can be regarded as the same as bending point P1 in the second embodiment. That is, point P2 is the end of the edge located on the inner periphery of the bent portion, of the two edges of the straight portion that extends linearly from the bent portion (connection portion 309a) toward the first side (-D1 side), closer to the bent portion.

[0161] Although not particularly shown, the connection portion 309a may be a curved portion of another type (a curved portion whose inner edge is also curved). Also, in the third embodiment, it has been described that the connection portion 9a of the extraction electrode 309 with the excitation electrode 7 may have a constant width. Similarly, the connection portion of the extraction electrode 309 with the mounting electrode 11 may also have a constant width by adopting a shape similar to that of the curved portion 209f (or a curved portion of another type).

[0162] In the extraction electrode 309, the direction (angle θ1) extending from the connection portion 309a (bent portion) to the mounting electrode 11 is arbitrary. For example, the angle θ1 may be greater than 0°, similar to the angle θ1 in the first embodiment, or may be 0°, similar to the angle of the second straight portion 209g with respect to the D1 direction in the second embodiment. In other words, the extraction electrode 309 may extend linearly in parallel to the first direction from the second edge portion (long side 7b) of the excitation electrode 7 to the mounting electrode 11 without overlapping with the first region A1.

[0163] <Fourth embodiment> 8 is a plan view showing a part of a quartz crystal element 401 according to the fourth embodiment. This figure corresponds to a part of FIG. 4 of the first embodiment.

[0164] In the first embodiment, the extraction electrode 9 extends from the excitation electrode 7 in a direction inclined obliquely in the D1 direction. However, as shown in Fig. 8, the extraction electrode 409 (connection portion 409a) may extend linearly from the excitation electrode 7 in a direction perpendicular to the D1 direction. As in the second embodiment, the extraction electrode 409 may include a bent portion 409f, thereby extending toward the mounting electrode 11 located on the -D1 side of the excitation electrode 7.

[0165] In the illustrated example, the bending portion 409f has a fan-like shape similar to the bending portion 209f in Fig. 7. However, the bending portion 409f may have another shape (the inner edge may also be curved). Furthermore, the direction after bending may be parallel to the D1 direction or may be inclined toward the D1 direction, as described in the second embodiment.

[0166] In the above embodiments, the quartz crystal elements 1, 201, 301, and 401 are each an example of a piezoelectric element. The quartz crystal device 101 is an example of a piezoelectric device. The quartz crystal plate 3 is an example of a piezoelectric plate. The D1 direction is an example of a first direction. The D2 direction is an example of a second direction. The -D1 side is an example of a first side of the first direction. The +D1 side is an example of a second side of the first direction. The short side 7a on the -D1 side of the excitation electrode 7 is an example of a first edge. The long side 7b of the excitation electrode 7 is an example of a second edge. The first surface 3a and second surface 3b of the quartz crystal plate 3 are each an example of a main surface of a piezoelectric plate.

[0167] The technology according to the present disclosure is not limited to the above-described embodiment and modifications, and may be implemented in various forms.

[0168] For example, the above-described embodiments may be combined as appropriate. For example, the shape of the connection portion 309a having a constant width shown in Fig. 7 may be applied to the shape of the connection portion 209a of the extraction electrode 209 shown in Fig. 6.

[0169] The piezoelectric material is not limited to quartz. For example, the piezoelectric material may be other single crystals or may be made of polycrystals (e.g., ceramics). Note that quartz to which an appropriate dopant is added may be considered a type of quartz. [Explanation of symbols]

[0170] 1...quartz crystal element (piezoelectric element), 3...quartz crystal blank (piezoelectric blank), 7...excitation electrode, 7a...short side (first edge of excitation electrode), 7b...long side (second edge of excitation electrode), 9...extraction electrode, 11...mounting electrode, 101...quartz crystal device (piezoelectric device), A1...first region.

Claims

1. a piezoelectric plate extending in a first direction and a second direction perpendicular to the first direction; a first excitation electrode overlapping one of the front and rear surfaces of the piezoelectric plate; a second excitation electrode overlapping the other of the front and rear sides of the piezoelectric plate; a first extraction electrode that is extracted from the first excitation electrode; a second extraction electrode extracted from the second excitation electrode; a first mounting electrode located on a first side in the first direction with respect to the first excitation electrode and connected to the first excitation electrode via the first extraction electrode; a second mounting electrode located on the first side with respect to the second excitation electrode and connected to the second excitation electrode via the second extraction electrode; It has each of the first excitation electrode and the second excitation electrode has a first edge portion located on the first side and extending along the second direction, and two second edge portions extending from both ends of the first edge portion toward a second side in the first direction; In planar perspective, a region surrounded by the first edge portion of the first excitation electrode, two imaginary lines extending parallel to the first direction from both ends of the first edge portion of the first excitation electrode to the first side, and a mounting-side imaginary line parallel to the second direction that contacts both the first mounting electrode and the second mounting electrode from the second side, or that contacts one of the first mounting electrode and the second mounting electrode from the second side and is spaced apart from the other of the first mounting electrode and the second mounting electrode from the second side; an area surrounded by the first edge portion of the second excitation electrode, two imaginary lines extending parallel to the first direction from both ends of the first edge portion of the second excitation electrode to the first side, and the mounting-side imaginary line; When the overlapping regions are referred to as first regions, the first extraction electrode extends, in a planar perspective view, with a constant width from a second edge portion, one of the two second edge portions of the first excitation electrode, that is located on a third side in the second direction, to the first mounting electrode without overlapping with the first region, the second extraction electrode extends, in a planar perspective view, with a constant width from a second edge portion of the second excitation electrode that is located on a fourth side in the second direction, without overlapping with the first region, to the second mounting electrode; When the distances from the two second edge portions to the two edge portions of the piezoelectric plate located on both sides in the second direction are referred to as first distances, a minimum value of each of the first distances on both sides of the first excitation electrode in the second direction is equal to or greater than half of a maximum value of a width of the first excitation electrode in the second direction and is greater than a maximum value of a distance from the first edge portion of the first excitation electrode to the mounting-side virtual line, a minimum value of each of the first distances on both sides of the second excitation electrode in the second direction is equal to or greater than half of a maximum value of a width of the second excitation electrode in the second direction and is greater than a maximum value of a distance from the first edge of the second excitation electrode to the mounting-side virtual line; Piezoelectric element.

2. The minimum value of each of the first distances on both sides of the first excitation electrode in the second direction is greater than the maximum value of the distance from the first edge of the first excitation electrode to the edge of the first side of the piezoelectric substrate, a minimum value of each of the first distances on both sides of the second excitation electrode in the second direction is greater than a maximum value of a distance from the first edge of the second excitation electrode to the edge of the piezoelectric base plate on the first side; The piezoelectric element according to claim 1 .

3. a piezoelectric plate extending in a first direction and a second direction perpendicular to the first direction; a first excitation electrode overlapping one of the front and rear surfaces of the piezoelectric plate; a second excitation electrode overlapping the other of the front and rear sides of the piezoelectric plate; a first extraction electrode that is extracted from the first excitation electrode; a second extraction electrode extracted from the second excitation electrode; a first mounting electrode located on a first side in the first direction with respect to the first excitation electrode and connected to the first excitation electrode via the first extraction electrode; a second mounting electrode located on the first side with respect to the second excitation electrode and connected to the second excitation electrode via the second extraction electrode; It has each of the first excitation electrode and the second excitation electrode has a first edge portion located on the first side and extending along the second direction, and two second edge portions extending from both ends of the first edge portion toward a second side in the first direction; In planar perspective, a region surrounded by the first edge portion of the first excitation electrode, two imaginary lines extending parallel to the first direction from both ends of the first edge portion of the first excitation electrode to the first side, and a mounting-side imaginary line parallel to the second direction that contacts both the first mounting electrode and the second mounting electrode from the second side, or that contacts one of the first mounting electrode and the second mounting electrode from the second side and is spaced apart from the other of the first mounting electrode and the second mounting electrode from the second side; an area surrounded by the first edge portion of the second excitation electrode, two imaginary lines extending parallel to the first direction from both ends of the first edge portion of the second excitation electrode to the first side, and the mounting-side imaginary line; When the overlapping regions are referred to as first regions, the first extraction electrode extends, in a planar perspective view, with a constant width from a second edge portion, one of the two second edge portions of the first excitation electrode, that is located on a third side in the second direction, to the first mounting electrode without overlapping with the first region, the second extraction electrode extends, in a planar perspective view, with a constant width from a second edge portion of the second excitation electrode that is located on a fourth side in the second direction, without overlapping with the first region, to the second mounting electrode; When the distances from the two second edge portions to the two edge portions of the piezoelectric plate located on both sides in the second direction are referred to as first distances, a minimum value of each of the first distances on both sides of the first excitation electrode in the second direction is equal to or greater than half of a maximum value of a width of the first excitation electrode in the second direction, a minimum value of each of the first distances on both sides of the second excitation electrode in the second direction is equal to or greater than half of a maximum value of a width of the second excitation electrode in the second direction, The second direction is the longitudinal direction of the piezoelectric plate, and the first direction is the lateral direction. Piezoelectric element.

4. a piezoelectric plate extending in a first direction and a second direction perpendicular to the first direction; a first excitation electrode overlapping one of the front and rear surfaces of the piezoelectric plate; a second excitation electrode overlapping the other of the front and rear sides of the piezoelectric plate; a first extraction electrode that is extracted from the first excitation electrode; a second extraction electrode extracted from the second excitation electrode; a first mounting electrode located on a first side in the first direction with respect to the first excitation electrode and connected to the first excitation electrode via the first extraction electrode; a second mounting electrode located on the first side with respect to the second excitation electrode and connected to the second excitation electrode via the second extraction electrode; It has each of the first excitation electrode and the second excitation electrode has a first edge portion located on the first side and extending along the second direction, and two second edge portions extending from both ends of the first edge portion toward a second side in the first direction; In planar perspective, a region surrounded by the first edge portion of the first excitation electrode, two imaginary lines extending parallel to the first direction from both ends of the first edge portion of the first excitation electrode to the first side, and a mounting-side imaginary line parallel to the second direction that contacts both the first mounting electrode and the second mounting electrode from the second side, or that contacts one of the first mounting electrode and the second mounting electrode from the second side and is spaced apart from the other of the first mounting electrode and the second mounting electrode from the second side; an area surrounded by the first edge portion of the second excitation electrode, two imaginary lines extending parallel to the first direction from both ends of the first edge portion of the second excitation electrode to the first side, and the mounting-side imaginary line; When the overlapping regions are referred to as first regions, the first extraction electrode extends, in a planar perspective view, with a constant width from a second edge portion, one of the two second edge portions of the first excitation electrode, that is located on a third side in the second direction, to the first mounting electrode without overlapping with the first region, the second extraction electrode extends, in a planar perspective view, with a constant width from a second edge portion of the second excitation electrode that is located on a fourth side in the second direction, without overlapping with the first region, to the second mounting electrode; When the distances from the two second edge portions to the two edge portions of the piezoelectric plate located on both sides in the second direction are referred to as first distances, a minimum value of each of the first distances on both sides of the first excitation electrode in the second direction is equal to or greater than half of a maximum value of a width of the first excitation electrode in the second direction and is equal to or greater than 200 μm; The minimum value of each of the first distances on both sides of the second excitation electrode in the second direction is equal to or greater than half the maximum value of the width of the second excitation electrode in the second direction and is equal to or greater than 200 μm. Piezoelectric element.

5. the piezoelectric substrate has two main surfaces located on the front and back sides thereof and a side surface connecting the two main surfaces, the first extraction electrode is connected to the first mounting electrode on one of the two main surfaces, The second extraction electrode is connected to the second mounting electrode on the other of the two main surfaces. The piezoelectric element according to any one of claims 1 to 4.

6. the first extraction electrode extends linearly to the first mounting electrode in a direction inclined with respect to the first direction, The second extraction electrode extends linearly to the second mounting electrode in a direction inclined with respect to the first direction. The piezoelectric element according to any one of claims 1 to 5.

7. The inclination angle of each of the first extraction electrode and the second extraction electrode with respect to the first direction is 30° or more and 45° or less. The piezoelectric element according to claim 6 .

8. The piezoelectric substrate is flat. The piezoelectric element according to any one of claims 1 to 7.

9. the first extraction electrode has a first bent portion that bends toward the first side while extending from the first excitation electrode to the first mounting electrode, the second extraction electrode has a second bent portion that bends toward the first side while extending from the second excitation electrode to the second mounting electrode, The first bent portion and the second bent portion each have a curved edge on the outer periphery. The piezoelectric element according to any one of claims 1 to 5.

10. the first extraction electrode has a first linear portion that extends linearly from the first bent portion toward the first side, an edge portion on an outer circumferential side of the first bent portion has an arc-shaped portion having a center at an end portion of the edge portion located on an inner circumferential side of the first bent portion, of the two edge portions of the first straight portion, the end portion being on the side of the first bent portion; the second extraction electrode has a second linear portion that extends linearly from the second bent portion toward the first side, The outer peripheral edge of the second bent portion has an arc-shaped portion having a center at an end of the inner peripheral edge of the second bent portion, of the two edges of the second straight portion, that is located on the second bent portion side. The piezoelectric element according to claim 9 .

11. the first extraction electrode has an edge portion located on an inner circumferential side of the first bent portion, the edge portion having two linearly extending portions that intersect each other at a first bent point; an edge portion on an outer circumferential side of the first bent portion has an arc shape centered on the first bending point, the second extraction electrode has an edge portion located on an inner circumferential side of the second bent portion, the edge portion having two linearly extending portions that intersect each other at a second bent point; The outer peripheral edge of the second bent portion is arc-shaped with the second bending point as the center. The piezoelectric element according to claim 10.

12. The piezoelectric element according to any one of claims 1 to 11, a package that holds the piezoelectric element; A piezoelectric device having:

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