JP7633928B2 - Piezoelectric vibration element and piezoelectric device - Google Patents

Description

This disclosure relates to a piezoelectric vibration element and a piezoelectric device having the piezoelectric vibration element.

Piezoelectric devices such as quartz crystal resonators and quartz crystal oscillators are known (see, for example, the following patent document). Such piezoelectric devices have a piezoelectric vibration element such as a quartz crystal vibration element, and a package that holds the piezoelectric vibration element. The piezoelectric vibration element has a piezoelectric body (for example, a quartz crystal blank), two excitation electrodes that overlap the piezoelectric body, and two extraction electrodes that are drawn out from the two excitation electrodes. The two extraction electrodes contribute to the mounting of the piezoelectric vibration element on the package by, for example, being joined to pads on the package with a conductive bonding material.

As the above-mentioned piezoelectric device, one that has a temperature-sensing element such as a thermistor is known. The temperature detected by the temperature-sensing element is used, for example, to compensate for changes in the characteristics of the piezoelectric vibration element caused by temperature changes.

The temperature sensor is mounted in a package. For example, in Patent Document 1, the package has a first recess and a second recess that opens on the opposite side to the first recess. The piezoelectric vibration element is housed in the first recess and mounted on the bottom surface of the first recess. The first recess is closed and sealed with a lid. The temperature sensor is a chip-type component, housed in the second recess and mounted on the bottom surface of the second recess. Specifically, two terminals of the temperature sensor and two pads located on the bottom surface of the second recess are joined by a conductive bonding material.

JP 2011-211340 A

For example, it is anticipated that a piezoelectric vibration element and a piezoelectric device will be provided that make it easier to bring the measurement temperature closer to the temperature of the piezoelectric body.

A piezoelectric vibration element according to one aspect of the present disclosure includes a piezoelectric body having a first region and a second region, two excitation electrodes having a portion overlapping the surface of the first region, two extraction electrodes extending from the two excitation electrodes, and a temperature-sensitive film having a portion overlapping the surface of the second region.

A piezoelectric device according to one aspect of the present disclosure includes the above-mentioned piezoelectric vibration element and a package that holds the piezoelectric vibration element.

The above configuration makes it easier to bring the measurement temperature closer to the temperature of the piezoelectric body, for example.

FIG. 1 is a perspective view showing a quartz crystal element according to a first embodiment. FIG. 2 is another perspective view showing the quartz crystal element of FIG. 1 . FIG. 2 is an exploded perspective view of a quartz crystal device as an example of use of the quartz crystal element according to the first embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 11 is a perspective view showing a quartz crystal element according to a second embodiment. FIG. 6 is another perspective view showing the crystal element of FIG. 5 . FIG. 11 is a cross-sectional view of a quartz crystal device as an example of a use of the quartz crystal element according to the second embodiment. FIG. 11 is a perspective view showing a quartz crystal element according to a third embodiment. FIG. 13 is a perspective view showing a quartz crystal element according to a fourth embodiment. FIG. 10 is another perspective view showing the crystal element of FIG. 9 . FIG. 13 is a perspective view showing a quartz crystal element according to a fifth embodiment. 12 is a cross-sectional view taken along line XII-XII of FIG. 13A and 13B are plan views showing modified examples of the planar shape of the buffer section. 14A and 14B are cross-sectional views showing modified examples of the cross-sectional shape of the buffer portion. 1 is a diagram showing quartz crystal elements according to various modified examples.

Below, an embodiment 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 match the actual ones. The dimensional ratios of the same components in the drawings also do not match. In addition, illustrations of details may be omitted, and some shapes may be illustrated in an exaggerated manner. However, the above does not deny that the actual dimensional ratios may be as in the drawings, and that features such as shapes and dimensional ratios may be extracted from the drawings.

For convenience, the drawings may include a Cartesian coordinate system D1-D2-D3. In the piezoelectric vibration element and piezoelectric device according to the embodiment, either direction may be vertical or horizontal. However, for convenience, the +D3 side may be expressed as upward. In addition, a plan view or plan perspective view refers to a view parallel to the D3 direction, unless otherwise specified.

In the explanation of the aspects (embodiments and variations) described relatively later, basically only the differences from the aspects described earlier will be described. Matters that are not specifically mentioned may be considered to be the same as the aspects described earlier or may be inferred from them. The explanation of the aspects described earlier may be applied to the aspects described later, unless a contradiction arises. In multiple aspects, corresponding components may be given the same reference numerals for convenience, even if there are differences.

The term "side" referring to the edge of a planar shape generally refers to the edge of a polygon (in other words, a straight line), but in the description of 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 the description of 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 the description of 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.

When referring to a rectangle or rectangular shape, unless otherwise specified, it does not have to be a square or a rectangle in the strict sense, and the corners may be chamfered. The same applies to polygons other than rectangles.

First Embodiment
(Overview of quartz crystal elements)
Fig. 1 is a perspective view of a crystal element 1 (an example of a piezoelectric vibration element) according to a first embodiment. Fig. 2 is a perspective view of the crystal element 1 seen from the opposite side to that in Fig. 1.

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

The quartz crystal element 1 has, for example, a quartz crystal blank 3 (an example of a piezoelectric body) and (at least) two conductor patterns 5 (in the illustrated example, a first conductor pattern 5A and a second conductor pattern 5B) that overlap the quartz crystal blank 3. The two conductor patterns 5 are not short-circuited to each other. Each conductor pattern 5 has, for example, an excitation electrode 7 and an extraction electrode 9 that is extracted from the excitation electrode 7. That is, the quartz crystal element 1 has a pair of excitation electrodes 7 and a pair of extraction electrodes 9 that are connected to the pair of excitation electrodes 7.

The pair of extraction electrodes 9 contribute to the mounting of the crystal element 1. Specifically, for example, as shown in FIG. 4 described later, the extraction electrodes 9 and the first pads 113 of the package 103 are bonded with a conductive bonding material 105 to mount the crystal element 1 on the package 103. Note that the crystal element 1 may be mounted on a member other than the package 103 (e.g., a circuit board), but for convenience, in the description of the embodiment, it may be assumed that the crystal element 1 is mounted on the package 103. When an AC voltage is applied to the pair of extraction electrodes 9 via the package 103, an AC voltage (electric field) is applied to the crystal blank 3 by the pair of excitation electrodes 7. This causes the crystal blank 3 to vibrate.

As shown in FIG. 1, the crystal element 1 further has a temperature-sensitive film 11. The temperature-sensitive film 11 is an element for measuring temperature, and is composed of, for example, a thin-film thermistor. The position of the temperature-sensitive film 11 is arbitrary. For example, the crystal blank 3 has a first region 3c (a portion on the +D1 side) in which at least a part (all of the excitation electrode 7 in the illustrated example) is located, and a second region 3d (a portion on the -D1 side) that is directly or indirectly connected to the first region 3c. In the illustrated example, the first region 3c and the second region 3d are indirectly connected via one or more (two in the illustrated example) connecting portions 3e. The temperature-sensitive film 11 has a portion located in the second region 3d. In the illustrated example, the entire temperature-sensitive film 11 overlaps the second region 3d. The temperature measured by the temperature-sensitive film 11 is used, for example, to compensate for changes in the characteristics of the crystal element 1 (crystal blank 3) caused by temperature changes.

Thus, in this embodiment, the temperature-sensitive film 11 (temperature-sensitive element) is not mounted on the package 103, but is included in the crystal element 1. This allows the temperature of the crystal blank 3 to be measured directly, compared to, for example, an embodiment in which the temperature-sensitive element is mounted on the package 103 (in other words, an embodiment in which the crystal element 1 and the temperature-sensitive element are separated). As a result, the measured temperature is more likely to follow the temperature of the crystal blank 3, improving the accuracy of temperature compensation. In addition, for example, the use of the temperature-sensitive film 11 (film-like element) instead of a chip-type temperature-sensitive element is advantageous for miniaturizing the package 103, and also reduces the effect of the mass of the temperature-sensitive element on the vibration of the crystal element 1.

The above is an overview of the crystal element 1 according to the first embodiment. In the following, the first embodiment will be described roughly in the following order.
1. The main body of the quartz crystal element 1 (excluding the temperature-sensitive film 11; FIGS. 1 and 2)
1.1. Overview of the configuration of the main body of the crystal element 1 1.2. Examples of shapes, dimensions, and materials of components of the main body of the crystal element 1 1.3. Second region 3d and connecting portion 3e
2. Temperature-sensitive membrane 11 (Figure 1)
2.1. Overview of the configuration of the temperature-sensitive film 11 2.2. Corresponding relationship between the configuration of the temperature-sensitive film 11 and the drawings 2.3. Position, shape, and dimensions of the temperature-sensitive film 11 2.4. Position, shape, and dimensions of the external electrode 11b (described later) 3. Example of use of the quartz crystal element 1 (FIGS. 3 and 4)
4. Summary of the First Embodiment

The first region 3c and the second region 3d are different parts of the crystal blank 3. The first region 3c is a region where at least a portion of the two excitation electrodes 7 overlap. The second region 3d is a region where at least a portion of the temperature-sensitive film 11 overlaps. As can be understood from this description, the excitation electrode 7 may have a portion located in the second region 3d, the temperature-sensitive film 11 may have a portion located in the first region 3c, and the excitation electrode 7 and the temperature-sensitive film 11 may overlap at least a portion. However, for convenience, in the description of the embodiment, the first region 3c is basically expressed as a region where the excitation electrode 7 is located and the temperature-sensitive film 11 is not located. Similarly, the second region 3d is basically expressed as a region where the excitation electrode 7 is not located and the temperature-sensitive film 11 is located.

1 and 2, the two regions connected to each other by the connecting portion 3e are labeled with the symbols of the first region 3c and the second region 3d. However, as will be understood from the explanation in the previous paragraph, the first region 3c may be defined as a range narrower or wider than the range to which the symbols are attached. Similarly, the second region 3d may be defined as a range narrower or wider than the range to which the symbols are attached. However, for convenience, in the explanation of the embodiment having the connecting portion 3e, the first region 3c and the second region 3d are basically expressed as being two regions connected to each other by the connecting portion 3e.

(1. The main body of the quartz crystal element (parts other than the temperature-sensitive film))
(1.1. Overview of the structure of the main body of the crystal element)
In the illustrated example, the crystal element 1 is a so-called AT-cut crystal element. In the AT-cut crystal element 1, the crystal blank 3 has a roughly plate-like shape. In other words, the crystal blank 3 is a crystal blank. The pair of excitation electrodes 7 overlap the first surface 3a and the second surface 3b of the plate-like crystal blank 3. The first surface 3a and the second surface 3b are the widest surfaces (main surfaces) of the plate shape, or in other words, the front and back surfaces of the plate shape. The pair of extraction electrodes 9 are, for example, extracted from the pair of excitation electrodes 7 to one end side (-D1 side) of the crystal blank 3.

In the AT-cut type, so-called thickness-shear vibration occurs when an AC voltage is applied to the crystal blank 3 by a pair of excitation electrodes 7. As described above, the crystal element 1 is mounted by bonding a pair of extraction electrodes 9 to the package 103 by a bonding material 105. At this time, the entire crystal element 1 or the first region 3c (first region 3c in the illustrated example) is supported in a cantilever manner by the package 103, for example. The manner in which the entire crystal element 1 is supported in a cantilever manner will be described later (FIGS. 9 and 10).

Examples of quartz crystal elements other than the examples shown in the figure include the following: A tuning fork-type element that uses bending vibration. A CT-cut or DT-cut element that uses contour shear vibration. An element with a cut angle other than AT-cut (e.g. BT-cut) that uses thickness shear vibration. Such elements also have, for example, a piezoelectric body (e.g. quartz crystal), two excitation electrodes that excite the piezoelectric body, and two extraction electrodes that are drawn out from the two excitation electrodes.

As can be seen from the above examples, the shape of the quartz element (quartz blank) is not limited to a plate shape, and may be various shapes. For example, a tuning fork-shaped quartz blank has a base and a pair of vibration arms extending parallel to each other from the base. Two or more excitation electrodes are located on each arm. The base contributes to supporting each of the pair of vibration arms in a cantilever shape. The two extraction electrodes are located, for example, on the base and/or the mounting arms extending from the base, and are joined to the package 103 by a bonding material 105.

The crystal elements of various shapes (including plate shapes) may, for example, be thin overall, or from another perspective, may be shaped in a way that allows the concept of a thickness direction (D3 direction in the illustrated example). The dimension in the thickness direction is smaller than the dimensions in directions perpendicular to the thickness direction and perpendicular to each other (D1 direction and D2 direction in the illustrated example). The thin crystal elements may be mounted on the package 103, for example, so as to face the first substrate surface 111c (in other words, a specified surface) of the package 103, which will be described later. In this case, the part excited by the excitation electrode (vibration part) may be supported in a cantilever shape, as in the illustrated example.

As described above, in the case where the quartz crystal element is mounted in the package 103 so as to face the first substrate surface 111c, the quartz crystal element may be configured so that either the +D3 side surface (first surface 3a) or the -D3 side surface (second surface 3b) can face the first substrate surface 111c in the overall configuration of the temperature-sensitive film 11, or it may not be configured so. For example, the quartz crystal element may be configured so as to be 180° rotationally symmetrical about an unillustrated axis of symmetry perpendicular to the thickness direction (for example, a center line parallel to the D1 direction in the illustrated example), or it may not be configured so.

In the description of this embodiment, for convenience, unless otherwise specified, it may be assumed that the quartz crystal element 1 is of the AT-cut type and/or that the quartz crystal blank 3 is a quartz crystal plate. In addition, in the description of this embodiment, the example mainly takes as an example a configuration 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.

In addition, the quartz blank 3 may have inclined surfaces (or, from another perspective, crystal planes) on the sides, etc., due to the anisotropy of quartz with respect to etching. In the description of the embodiment, the existence of such inclined surfaces is basically 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 consideration, as long as it does not lack rationality or cause contradictions. For example, when referring to the length of the quartz blank 3 in the D1 direction, the 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 consideration).

(1, 2. Examples of shapes, dimensions and materials of components of the main body of a quartz crystal element)
As shown in the example, in a quartz crystal element 1 (not necessarily an AT cut type) having a plate-shaped quartz crystal blank 3, a pair of excitation electrodes 7 overlapping both main surfaces of the quartz crystal blank 3, and a pair of extraction electrodes 9 led out from the pair of excitation electrodes 7, the more specific configurations (planar shape, etc.) of the quartz crystal blank 3, the excitation electrodes 7, and the extraction electrodes 9 may be set as appropriate.

For example, when the temperature-sensitive film 11 is not taken into consideration, the crystal blank 3, the pair of excitation electrodes 7, and/or the pair of extraction electrodes 9 may or may not be configured so that either the +D3 side surface (first surface 3a) or the -D3 side surface (second surface 3b) can face the first substrate surface 111c (illustrated example). In other words, these shapes may or may not be 180° rotationally symmetric with respect to an unillustrated axis of symmetry perpendicular to the thickness direction (e.g., a center line parallel to the D1 direction). In the illustrated example, the crystal blank 3 and the pair of excitation electrodes 7 are 180° rotationally symmetric, but the pair of extraction electrodes 9 are not 180° rotationally symmetric.

For example, the planar shape of the entire crystal blank 3 and/or the first region 3c may be rectangular (as shown in the example), circular, elliptical, or a polygon other than a rectangle. The planar shape of the entire crystal blank 3 and/or the first region 3c may be a shape in which any number of sides of a polygon (for example, one, two, three, or four sides of a rectangle) are curved outward. The planar shape of the entire crystal blank 3 and/or the first region 3c may have a protrusion or a notch in part. For example, the planar shape of the entire crystal blank 3 and/or the first region 3c may be a shape whose longitudinal direction is the D1 direction (a shape in which the maximum length in the D1 direction is longer than the maximum length in the D2 direction), or may be a shape in which such a distinction cannot be made.

For example, the thickness of the entire crystal blank 3 and/or the first region 3c may be constant (as shown in the example) or may not be constant. Examples of the latter, not shown in the figures, include the following: A so-called mesa type in which the central region (mesa portion) that is excited by overlapping with a pair of excitation electrodes 7 is thicker than the peripheral region. Conversely to the above, a so-called inverted mesa type in which the central region (inverted mesa portion) that is excited by overlapping with a pair of excitation electrodes 7 is thinner than the peripheral region. A type having a vibration portion that is excited by overlapping with a pair of excitation electrodes 7, and a fixed portion adjacent to a part of the edge of the vibration portion (for example, one side, two sides, or three sides), that is thicker than the vibration portion, and where a pair of extraction electrodes 9 are located. A bevel type in which the thickness becomes thinner in the peripheral portion as it approaches the outer periphery.

In addition, for example, the planar shape of the excitation electrode 7 may be similar to the planar shape of the entire crystal blank 3 and/or the first region 3c (or the planar shape of the mesa portion, inverted mesa portion or vibration portion described above; the same applies below in this paragraph) (as in the illustrated example), or it may not be such a shape. Examples of the former include a state in which the planar shape of the entire crystal blank 3 and/or the first region 3c minus the planar shape of the excitation electrode 7 is rectangular-rectangular, circular-circular, or elliptical-elliptical. Examples of the latter include a state in which the planar shape of the entire crystal blank 3 and/or the first region 3c minus the planar shape of the excitation electrode 7 is rectangular-circular, rectangular-elliptical, or elliptical-rectangular. Regardless of whether the planar shape of the excitation electrode 7 is similar to the planar shape of the entire crystal blank 3 and/or the first region 3c, the above description of the planar shape of the crystal blank 3 may be applied to the planar shape of the excitation electrode 7, unless a contradiction arises.

Each extraction electrode 9 has, for example, a wiring portion 9a extending from the excitation electrode 7 and a pad-shaped terminal portion 9b connected to the excitation electrode 7 via the wiring portion 9a. The terminal portion 9b is a portion that is joined to the package 103 and has a width greater than that of the wiring portion 9a. As described above, the crystal element 1 in the illustrated example is assumed to be supported by the package 103 by joining the lower surface of the crystal element 1 to the first substrate surface 111c of the package 103. Therefore, each extraction electrode 9 has a terminal portion 9b only on the lower surface. Unlike the above description, in the illustrated example, the terminal portion 9b on the lower surface may be considered to have a larger area (length in the D1 direction from another perspective) than the terminal portion 9b on the upper surface. Of course, unlike the illustrated example, terminal portions 9b of equal size may be provided on both the upper surface and the lower surface.

The position, shape, and dimensions of the wiring portion 9a and the terminal portion 9b are arbitrary. For example, as in the illustrated example, in a mode in which the entire crystal element 1 or the first region portion 3c (in the illustrated example, the first region portion 3c) is supported in a cantilever shape at one end in a predetermined direction (here, the D1 direction), the wiring portion 9a may extend parallel to the D1 direction (illustrated example), may extend obliquely to the D1 direction, may extend linearly (illustrated example), or may have a bent or curved portion. In any of these modes, the wiring portion 9a may be considered to extend from the excitation electrode 7 to the first side (here, the -D1 side) in a predetermined direction. In addition, the terminal portion 9b may be located at the end of the first side (-D1 side) of at least one of the upper and lower surfaces of the entire crystal element 1 or the first region portion 3c. Whether or not it is located at the end may be determined rationally. For example, if the edge of the -D1 side of terminal portion 9b coincides with the edge of the -D1 side of at least one of the upper and lower faces, or is close to the edge of the -D1 side of at least one of the upper and lower faces at a distance of less than 1/2 the length of terminal portion 9b in the D1 direction, terminal portion 9b may be considered to be located at the end.

The dimensions of the crystal element 1 are arbitrary. However, in a crystal element 1 that utilizes thickness-shear vibration, the thickness of the crystal blank 3 (in this paragraph, unless otherwise specified, the thickness at the portion where the excitation electrode 7 overlaps) is a factor that determines the frequency of the oscillation signal. For example, as is well known, in an AT-cut crystal element, the relationship f = 1.67 x n/t basically holds. Here, f is the frequency (MHz), n is the order of vibration used, and t (mm) is the thickness. The crystal element 1 may utilize either the fundamental mode or the overtone mode.

The following are examples of the range of dimensions of the quartz crystal element 1 (or the quartz crystal blank 3). The length of the entire quartz crystal element 1 or the first region 3c in the longitudinal direction (D1 direction) may be 500 μm or more and 1500 μm or less. The length of the entire quartz crystal element 1 or the first region 3c in the transverse direction (D2 direction) may be 300 μm or more and 800 μm or less (however, this is shorter than the length of the quartz crystal element 1 in the D1 direction). The thickness of the quartz crystal element 1 may be 5 μm or more and 100 μm or less. The above are examples of the range of dimensions assuming a relatively small AT-cut type quartz crystal element 1, but may be referred to as examples of the dimensions of various other quartz crystal elements.

The material of the conductor 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 conductor pattern 5 may be composed of a single conductor layer made of a single material, or may be composed of a plurality of conductor layers made of different materials stacked together. The conductor pattern 5 may have the same material composition over its entire area, or may have different material composition depending on the region.

It has been mentioned that the crystal element may have various configurations (for example, the crystal blank 3 may not be plate-shaped). As can be understood from the tuning fork-shaped crystal element, the number of excitation electrodes is not limited to two, and may be three or more. However, two or more excitation electrodes that are at the same potential may be regarded as one excitation electrode. In addition, the two excitation electrodes to which different potentials are applied are not limited to those located on both sides in the thickness direction of the crystal blank, and at least one of them may be located on a side (for example, a side of a tuning fork-shaped arm). From another perspective, the two excitation electrodes may be located on two sides of the crystal blank that face in different directions (for example, opposite directions or directions that intersect with each other (for example, perpendicular)). The extraction electrode may include a wiring portion that extends in a more complicated path.

(1.3. Second Region and Connecting Portion)
As described above, the second region 3d is connected to the first region 3c by at least one (two in the examples of Figs. 1 and 2) connecting portion 3e. It is also possible to consider that the buffer portion 13 consisting of a through hole is located between the first region 3c and the second region 3d. In the illustrated example, the buffer portion 13 is composed of a slit (a type of through hole) extending in a direction (D2 direction) intersecting (for example, perpendicular to) the direction (D1 direction) from the first region 3c to the second region 3d. In the illustrated example, a plurality (three) of the buffer portions 13 are arranged in series. The slits on both sides in the D3 direction are notches from another perspective.

The buffer portion 13, for example, contributes to reducing the effect of the mass of the temperature-sensitive membrane 11 on the vibration in the first region 3c. From another perspective, the connecting portion 3e contributes to transmitting heat from the first region 3c to the temperature-sensitive membrane 11.

In the example of Figures 1 and 2, the first region 3c has a configuration similar to that of a typical cantilever-shaped quartz element or a similar quartz element. The quartz element 1 has a configuration in which the second region 3d and the connecting portion 3e are added to the first region 3c. In other words, the entire two extraction electrodes 9 (terminal portions 9b from another perspective) are located in the first region 3c.

The position, shape and dimensions of the second region 3d are arbitrary. In the example of FIG. 1 and FIG. 2, the second region 3d is located on the side (-D1 side) where the extraction electrode 9 is located with respect to the excitation electrode 7 with respect to the first region 3c. The second region 3d also extends (for example, parallel) along one edge (one side) of the four edges of the first region 3c with a generally constant width. From another perspective, the second region 3d is a rectangle with a longitudinal direction in a direction (D2 direction) that intersects (for example, perpendicular to) the direction (D1 direction) from the first region 3c to the second region 3d. The length of the second region 3d in a direction (here, the D2 direction) along one edge of the first region 3c may be shorter, equal (in the illustrated example), or longer than the length of the one edge. The width (here, the length in the D1 direction) of the second region 3d is arbitrary.

As already mentioned, the planar shape of the entire crystal element 1 and/or the first region 3c may be various shapes other than rectangular. As can be understood from this, in a mode in which the overall shape of the second region 3d or the shape of the edge of the second region 3d on the first region 3c side is a shape that follows (for example, is parallel to) the edge of the first region 3c, the shape of the second region 3d is not limited to a rectangular shape. For example, the shape of the second region 3d may be a shape that extends in a curved shape as a whole. Also, for example, in the second region 3d, the edge on the first region 3c side (here, the +D1 side) may be curved, and the edge on the opposite side (here, the -D1 side) may be linear (a shape that becomes wider on both sides in the D2 direction).

Unlike the illustrated example, the shape of the second region 3d may not be a shape that has the edge of the first region 3c on the second region 3d side as the longitudinal direction. For example, in the second region 3d, the width (length in the D1 direction) of the second region 3d may be greater than the length of one edge of the first region 3c on the second region 3d side. Also, for example, the length (D2 direction) of the second region 3d may be shorter than the length of one edge of the first region 3c on the second region 3d side and may be equal to or less than the width of the second region 3d. Furthermore, the shape of the second region 3d may be a shape that is difficult to grasp as being along the shape of the edge of the first region 3c on the second region 3d side (here, the -D1 side). For example, the first region 3c may be circular or elliptical, and the second region 3d may be square.

Here is an example of the dimensions of the second region 3d. The length (e.g., minimum width, average width, or maximum width) of the second region 3d in the direction from the first region 3c to the second region 3d (here, the D1 direction) may be 1/20 or more, 1/10 or more, 1/5 or more, 1/3 or more, or 1/2 or more, or may be 2 times or less, 1 time or less, 1/2 or less, or 1/3 or less, of the length of the first region 3c in the above direction (here, the D1 direction), the length in the direction perpendicular to the above direction (here, the D2 direction), or the maximum length of the short side direction of the first region 3c (if the short side direction cannot be specified, an appropriate direction). The above lower limit and upper limit may be combined with any one that does not contradict each other. The area of the second region 3d may be 1/20 or more, 1/10 or more, 1/5 or more, 1/3 or more, 1/2 or more, 1 or more, or 2 or more times the area of the first region 3c, or 5 or less, 2 or less, 1 or less, 1 or less, 1/2 or less, or 1/3 or less. The above lower and upper limits may be combined in any manner so as not to contradict each other. In the above description of this paragraph, the term "first region 3c" may be replaced with "excitation electrode 7".

The number, position, shape, and dimensions of the connecting parts 3e are arbitrary. For example, the number of connecting parts 3e may be any number equal to or greater than one. Also, for example, the position of the connecting part 3e may be the center of the second region 3d in the direction along the edge of the first region 3c (here, direction D2), or may be between the center and the end (in the illustrated example). In the connecting part 3e, either the length (length protruding from the first region 3c) or the width (length in the direction along the edge of the first region 3c) may be larger or may be equal to each other, and in the illustrated example, the width is larger than the length. Also, the width of the connecting part 3e may be constant or may not be constant.

From another perspective, the number, position, shape, and dimensions of the buffer section 13 are arbitrary. For example, the number of the buffer sections 13 may be any number equal to or greater than one. As can be understood from the above description of the shape of the second region 3d, in the illustrated example, the buffer section 13 extends along (more specifically, parallel to) the edge of the first region 3c with a roughly constant width. More specifically, the buffer section 13 extends linearly. Also, as can be understood from the above description of the shape of the second region 3d, the buffer section 13 is not limited to being linear, nor is it limited to being of a constant width. For example, the buffer section 13 may extend in a curved shape with a constant width, or the width may vary.

In a cross section perpendicular to the direction in which the buffer section 13 extends in a plan view (here, a cross section parallel to the D1-D3 plane), the shape and dimensions of the buffer section 13 are arbitrary. For example, the buffer section 13 may penetrate the crystal blank 3 with a constant width, or the width may be narrower toward the +D3 side, the -D3 side, or the midway position in the D3 direction. As will be understood from the modified example (FIG. 15) described later, the buffer section 13 may extend in any appropriate direction. The cross-sectional shape and/or dimensions of the buffer section 13 may differ depending on the direction in which the buffer section 13 extends. The width of the buffer section 13 (e.g., minimum width, maximum width, or average width) may be smaller, equal, or larger than the thickness of the crystal blank 3 (e.g., minimum thickness, maximum thickness, or average thickness).

(2. Temperature-sensitive membrane)
(2.1. Overview of the structure of the temperature-sensitive membrane)
The type of the temperature-sensitive film 11 (or, from another point of view, the temperature detection principle) is arbitrary, and may be, for example, a thermistor, a resistance temperature detector, a thermocouple, or a diode. The specific configuration of each type of temperature sensor is also arbitrary. Note that, for convenience, in the description of the embodiment, the temperature-sensitive film 11 may be expressed as a thermistor, without any particular mention.

It may be reasonably determined based on technical common sense that the temperature-sensitive film 11 is not a chip-type temperature-sensitive element. For example, the temperature-sensitive film 11 is composed of one or more layers that overlap the film-forming target (quartz blank 3), while the chip-type temperature-sensitive element has a packaged structure that is mounted by a bonding material (e.g., bumps). From another perspective, the absolute thickness of the temperature-sensitive film 11, or its thickness relative to the thickness of the quartz blank 3, does not necessarily need to be extremely thin.

Although not specifically shown, we will take as an example an embodiment in which the temperature-sensitive film 11 is a thermistor, and explain how the specific configuration can take various forms.

Thermistors, for example, have, as a basic component, a resistive film whose resistance value changes with temperature. The material of the resistive film may be, for example, an oxide (for example, a composite oxide) or a nitride (for example, a composite nitride). The oxide or nitride may contain one or more of nickel (Ni), manganese (Mn), cobalt (Co), aluminum (Al), iron (Fe), and chromium (Cr). The resistive film may have, for example, only one layer of a single material, or may have two or more layers of different materials. In addition, the resistive film may have the same material composition throughout its entirety in a planar view, or the material composition may differ depending on the region.

The resistive film may directly overlap the surface of the crystal blank 3 (area where the conductor pattern 5 is not arranged) or may overlap via an insulating film. The resistive film may have a portion that overlaps the conductor pattern 5 (e.g., the extraction electrode 9) via the insulating film, or may not have such a portion. In the former embodiment, the insulating film may overlap the entire resistive film, or may overlap only a portion of the resistive film including the portion that overlaps the conductor pattern 5. The insulating film has, for example, a resistivity higher than that of the resistive film.

The material of the insulating film is arbitrary, and may be, for example, an inorganic material, an organic material, or a combination of both. Examples of inorganic materials include silicon dioxide (SiO ₂ ) and silicon nitride (Si ₃ N ₄ ). Examples of organic materials include various resins (e.g., epoxy-based resins or silicone-based resins). The insulating film may have, for example, only one layer of a single material, or may have two or more layers of different materials. In addition, the insulating film may have the same material composition throughout its entirety in a plan view, or may have different material composition depending on the region.

The resistive film may be exposed to the space formed by the package 103 (from another perspective, inside the recess R1 described later), or may be covered by an insulating coating film. The coating film has, for example, a resistivity higher than that of the resistive film. The coating film may be provided for various purposes. For example, the coating film may contribute to protecting the resistive film or the electrodes described later. Examples of such protection include protection from corrosion, as well as protection from laser light that cuts the excitation electrode 7 to adjust the frequency of the crystal element 1. The coating film may also contribute to insulating the resistive film from the surrounding space, making it easier for the temperature of the resistive film to follow the temperature of the crystal blank 3. The material of the coating film is arbitrary. For example, the description of the material of the insulating film in the previous paragraph may be used for the coating film.

A voltage may be applied to the resistive film by a pair of application electrodes of an appropriate arrangement and shape. For example, the pair of application electrodes may be located at both ends of the resistive film in the longitudinal direction (or transverse direction) in a plan view, and may apply a voltage to the resistive film in the longitudinal direction (or transverse direction). In this embodiment, at least a portion of the pair of application electrodes connected to the resistive film may overlap the lower surface (crystal blank 3 side) of the resistive film, or may overlap the upper surface of the resistive film. In addition, the pair of application electrodes may face each other across the resistive film in the thickness direction, and apply a voltage to the resistive film in the thickness direction. The pair of application electrodes may be a pair of comb-tooth electrodes that overlap the upper or lower surface of the resistive film and are interdigitated with each other. In the above various embodiments, the insulating film (or another insulating film) described above may or may not be interposed between at least one application electrode overlapping the lower surface of the resistive film and the crystal blank 3.

The material of the application electrode is arbitrary. For example, at least a part of the material of the application electrode may be the same as at least a part of the material of the conductor pattern 5, or may be different. In any case, the above-mentioned explanation of the material of the conductor pattern 5 (specific examples of metals, the presence or absence of layers of different materials, the presence or absence of regions of different materials, etc.) may be used to explain the material of the application electrode. The same applies to the materials of the external electrode 11b and relay conductor described below.

(2.2. Structure of the temperature-sensitive film and its correspondence to the drawings)
As can be understood from the above description, the temperature-sensitive film 11 may have various configurations (e.g., a resistive film, an insulating film, a coating film, and an application electrode). In FIG. 1 (and other drawings), the configuration of the temperature-sensitive film 11 is shown as follows.

In FIG. 1 (as well as other drawings), the temperature-sensitive film 11 has a film body 11a and a pair of external electrodes 11b. A voltage is applied to the film body 11a, for example, via the pair of external electrodes 11b. From another perspective, the film body 11a outputs a signal with an intensity according to the temperature from at least one of the pair of external electrodes 11b.

As can be understood from the above explanation using the thermistor as an example, the film body 11a may have only a functional part that directly contributes to temperature detection (e.g., a resistive film in the case of a thermistor), or may have an insulating film, a coating film, an application electrode, and/or a relay conductor, as described in the next paragraph, that overlaps the functional part.

For example, in the case where the temperature-sensitive film 11 is a thermistor, the external electrode 11b may be a part or all of an application electrode that applies a voltage directly to the resistive film (directly in contact with the resistive film), or may be an electrode that is electrically connected to the application electrode. In the latter case, the external electrode 11b may be directly connected to the application electrode by, for example, overlapping a part of the application electrode with the application electrode, or may be indirectly connected to the application electrode via a relay conductor (e.g., a conductor layer different from both the application electrode and the external electrode 11b).

From another perspective, the pair of external electrodes 11b may be considered to be shown in their entirety or in part in FIG. 1. In the latter case, the part may be, for example, a part of the pair of external electrodes 11b that is covered by a coating film and is exposed from the coating film. The part may be considered to be an extracted part of the pair of external electrodes 11b that contributes to the connection with the package 103 (other parts of the pair of external electrodes 11b are also exposed, but are omitted from the drawing).

To give a specific example, as already described, the temperature-sensitive film 11 may have a pair of application electrodes that overlap the functional part on both sides of a predetermined direction in a plan view (e.g., the direction in which the functional part (resistive film) extends). In this case, the pair of external electrodes 11b shown in the figure may be, for example, the entire pair of application electrodes, or a part of the pair of application electrodes (exposed parts or extracted parts), or a pair of terminals that are directly or indirectly connected to the pair of application electrodes.

For example, the temperature-sensitive film 11 may have a pair of application electrodes sandwiching the resistive film in the thickness direction, as described above. In this case, the pair of external electrodes 11b shown in the figure may be parts of the pair of application electrodes (exposed parts or extracted parts), or may be a pair of terminals directly or indirectly connected to the pair of application electrodes. In the former embodiment, the pair of external electrodes 11b may be the end of one application electrode in a planar view and the end of the other application electrode in a planar view.

For example, the temperature-sensitive film 11 may have a pair of comb-tooth electrodes as a pair of application electrodes, as described above. The pair of external electrodes 11b shown in the figure may be a part (exposed part or extracted part) of a pair of conductor patterns including the pair of comb-tooth electrodes, or a pair of terminals directly or indirectly connected to the pair of comb-tooth electrodes. More specifically, the pair of comb-tooth electrodes may have, for example, a pair of bus bars facing each other and a plurality of electrode fingers extending from each bus bar to the other bus bar. The part of the pair of conductor patterns may be, for example, a part extending from the pair of bus bars. The pair of terminals may be, for example, directly or indirectly connected to the pair of bus bars.

In addition, in a plan view, the relationship between the shape of the temperature-sensitive film 11 and the arrangement of the pair of comb-tooth electrodes is arbitrary. For example, as in the illustrated example, when at least a part of the temperature-sensitive film 11 (all of it in the example of FIG. 1) has a shape having a longitudinal direction and a lateral direction (referred to as a first shape in this paragraph), the pair of comb-tooth electrodes may be arranged so that a pair of bus bars extend in the longitudinal direction and multiple electrode fingers extend in the lateral direction. In an embodiment in which the temperature-sensitive film 11 has multiple first shapes, a pair of comb-tooth electrodes may be provided for each first shape.

(2.3. Position, shape and dimensions of temperature-sensitive membrane)
The position, shape and dimensions of the thermosensitive film 11 in the second region 3d are arbitrary. The description of the position, shape and dimensions of the thermosensitive film 11 may be applied to the position, shape and dimensions of the film body 11a, unless a contradiction occurs. As can be understood from the above example of the thermistor, the position, shape and dimensions of the film body 11a are the position, shape and dimensions of the functional part in an embodiment in which the film body 11a consists only of a functional part (resistive film in the thermistor), and are the position, shape and dimensions of the entire functional part and other parts in an embodiment in which the film body 11a includes other parts (insulating film, coating film, application electrode and/or relay conductor). However, the description of the position, shape and dimensions of the thermosensitive film 11 may be applied to the position, shape and dimensions of the functional part, or a combination of the functional part and other parts directly above it, in an embodiment in which the film body 11a includes other parts other than the functional part, unless a contradiction occurs.

The temperature-sensitive film 11 is located, for example, on the first surface 3a of the crystal blank 3 (the surface opposite to the side facing the first substrate surface 111c of the package 103). The planar shape of the temperature-sensitive film 11 is, for example, rectangular, and more specifically, in the example of FIG. 1, is a rectangle that does not include a square. The length of the longitudinal direction (e.g., maximum length) of the temperature-sensitive film 11 is relatively long (e.g., twice or more) compared to the length of the lateral direction (e.g., maximum width) of the temperature-sensitive film 11, and the shape of the temperature-sensitive film 11 can be said to be elongated. From another perspective, the temperature-sensitive film 11 has a shape having multiple edges (four sides) parallel to the multiple edges (four sides) of the second region 3d. The distance between the edge of the second region 3d and the edge of the temperature-sensitive film 11 may be the same for the four sets of edges, or may be different depending on the set of edges. In the example of FIG. 1, the temperature-sensitive film 11 overlaps most of the surface on the +D3 side of the second region 3d (e.g., 80% or more of the surface area).

However, unlike the illustrated example, the planar shape of the temperature-sensitive membrane 11 does not have to be rectangular or elongated. For example, the planar shape of the temperature-sensitive membrane 11 may be square, circular, elliptical, or polygonal, or may be a rectangle with curved short sides. From another perspective, the edge of the temperature-sensitive membrane 11 may be straight or curved, and may have bent portions, curved portions, and/or stepped portions. From yet another perspective, the width of the temperature-sensitive membrane 11 may change depending on the position in the longitudinal direction.

From another perspective, the edge of the temperature-sensitive film 11 does not have to be parallel to the edge of the second region 3d. For example, in a configuration in which the edge of the second region 3d on the first region 3c side (here, the +D1 side) is curved with a concave toward the first region 3c side, the edge of the temperature-sensitive film 11 on the first region 3c side may be straight. Similarly, in a configuration in which the edge of the second region 3d on the opposite side to the first region 3c side (here, the -D1 side) is curved with a concave toward the first region 3c side, the edge of the temperature-sensitive film 11 on the opposite side to the first region 3c side may be straight.

Here is an example of the dimensions of the thermosensitive film 11. The length (e.g., minimum width, average width, or maximum width; the same applies hereinafter in this paragraph) of the thermosensitive film 11 in the direction from the first region 3c to the second region 3d (here, the D1 direction) may be 1/10 or more, 1/5 or more, 1/3 or more, 1/2 or more, or 2/3 or more, or may be 1 time or less, 2/3 or less, 1/2 or less, or 1/3 or less. The above lower and upper limits may be combined in any way so as not to contradict each other.

The explanation in the previous paragraph may be applied to dimensions in different directions by replacing the term of length in the direction from the first region 3c to the second region 3d with the term of length in the direction perpendicular to the direction from the first region 3c to the second region 3d (here, the D2 direction) or with the term of length along the second region 3d (for example, the length along the center line of the curved second region 3d). The explanation in the previous paragraph may also be applied to the upper and/or lower limits of the area by replacing the term of length in the direction from the first region 3c to the second region 3d with the term of area. Previously, examples of the dimensions of the second region 3d were described in comparison with the first region 3c (or the excitation electrode 7). The dimensions of the second region 3d obtained by selecting any one of the examples of the upper and/or lower limits of the second region 3d in the description may be applied to the previous paragraph to derive examples of the dimensions of the temperature-sensitive film 11 in comparison with the first region 3c or the excitation electrode 7.

In the illustrated example, the temperature-sensitive film 11 spreads over almost the entire second region 3d. Therefore, the geometric center of the temperature-sensitive film 11 roughly coincides with the geometric center of the second region 3d. However, the geometric center of the temperature-sensitive film 11 may be shifted from the geometric center of the second region 3d in the direction from the first region 3c to the second region 3d (here, direction D1) and/or in the direction along the edge of the first region 3c on the second region 3d side (here, direction D2).

The temperature-sensitive film 11 may have a generally constant thickness throughout its entire area, or may have multiple areas with different thicknesses. The upper surface of the temperature-sensitive film 11 may be, for example, flat, curved, or uneven. An example of an uneven shape is a shape with multiple flat surfaces with different heights. An example of such a shape is a shape in which the presence or absence of the resistive film and/or relay conductor is revealed on the upper surface of the coating film that covers them.

The specific thickness of the temperature-sensitive film 11 is arbitrary. For example, the maximum thickness or average thickness of the temperature-sensitive film 11 may be 1/300 or more, 1/200 or more, 1/100 or more, 1/50 or more, 1/30 or more, 1/10 or more, 1/5 or more, or 1/2 or more of the minimum thickness, average thickness, or maximum thickness of the quartz blank 3, and may be 2 times or less, 1 time or less, 1/5 or less, 1/10 or less, or 1/100 or less. The above lower limit and upper limit may be combined with any of them so as not to cause any contradiction. The thickness of the temperature-sensitive film 11 may be, for example, 0.05 μm or more, 0.1 μm or more, 1 μm or more, 5 μm or more, or 10 μm or more, and may be 100 μm or less, 50 μm or less, or 10 μm or less. The above lower limit and upper limit may be combined with any of them so as not to cause any contradiction.

(2.4. Position, shape and dimensions of external electrodes)
In the illustrated example, the pair of external electrodes 11b are located within the arrangement area of the film body 11a. For example, the external electrodes 11b overlap any of the components (for example, the functional part (resistive film)) constituting the film body 11a. However, the external electrodes 11b may be located outside the arrangement area of the film body 11a. Furthermore, as can be understood from the extraction electrode 9, the external electrodes 11b may be located (may have a portion located) on a surface (side surface and/or second surface 3b) other than the surface on which the film body 11a is located (here, the first surface 3a). In this case, the external electrodes 11b may pass through, for example, the side surface of the second region portion 3d (in the illustrated example, the surface on the -D2 side, the surface on the +D2 side, the surface on the -D1 side, and/or the surface on the +D1 side). In addition, when a through hole penetrating the second region portion 3d in the thickness direction is provided, the external electrodes 11b may pass through the through hole.

As mentioned above, the structure of the film body 11a may be various. For example, a relay conductor may be interposed between the application electrode that applies a voltage to the functional part (resistive film in the case of a thermistor) and the external electrode 11b to electrically connect the two. Furthermore, at least two of the application electrode, relay conductor, and external electrode 11b may cross each other via an insulator, or two or more (e.g., two or more layers) of relay conductors may be interposed between the application electrode and the external electrode 11b. As can be understood from this, even in a mode in which the external electrode 11b is located within the arrangement area of the film body 11a, the position, shape, and dimensions of the external electrode 11b can be any position, shape, and dimensions, regardless of the position, shape, and dimensions of the functional part.

In the illustrated example, the pair of external electrodes 11b are located in different regions in the direction in which the thermosensitive membrane 11 (or the membrane body 11a; the same applies in this paragraph and the next paragraph unless a contradiction occurs) extends (the longitudinal direction in another perspective). However, unlike the illustrated example, for example, the pair of external electrodes 11b may be aligned in the width direction of the thermosensitive membrane 11. Also, in the illustrated example, the pair of external electrodes 11b are located at both ends of the thermosensitive membrane 11. Examples of configurations other than those illustrated include a configuration in which at least one of the pair of external electrodes 11b is located in the center of the thermosensitive membrane 11 in its extension direction, and a configuration in which both of the pair of external electrodes 11b are located at one end of the thermosensitive membrane 11.

The planar shape of the external electrode 11b may be various shapes such as a rectangular shape (as shown in the example) or a circular shape. The dimensions of the external electrode 11b are also arbitrary. For example, as can be understood from the above positional explanation, the length of the external electrode 11b in the width direction of the temperature-sensitive membrane 11 may be more than 1/2 the width of the temperature-sensitive membrane 11, or may be less than 1/2. Furthermore, the length of the external electrode 11b in the longitudinal direction of the temperature-sensitive membrane 11 and the length of the external electrode 11b in the width direction of the temperature-sensitive membrane 11 may be greater than or equal to each other.

(3. Examples of using quartz crystal elements)
Fig. 3 is an exploded perspective view of a quartz crystal device 101 as an example of use of the quartz crystal element 1. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3.

The crystal device 101 is, for example, an electronic component that has an approximately rectangular parallelepiped shape overall. 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, for example, surface-mounted with its bottom surface facing the top surface of a mounting base (e.g., a circuit board) not shown.

The crystal device 101 is configured as, for example, a crystal oscillator. The crystal device 101 has, 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 contributes to the electrical connection between the crystal element 1 and the mounting base (not shown).

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

The insulating member 111 is shaped to have 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 material of the substrate portion 111a and the frame portion 111b is arbitrary, and is, for example, 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 bottom surface of the crystal device 101.

The conductors possessed by the base 107 include, for example, the following: Two first pads 113 and two second pads 115 electrically connected to the crystal element 1. Four external terminals 117 for mounting the crystal device 101 to the mounting base. Four wiring conductors 119 connecting the above four pads (113 and 115) to the four external terminals 117.

The first pad 113 is bonded to the extraction electrode 9 by the bonding material 105. This fixes the crystal element 1 and electrically connects the excitation electrode 7 to the external terminal 117. The second pad 115 is connected to the external electrode 11b of the temperature-sensitive film 11 by a bonding wire 121. This electrically connects the temperature-sensitive film 11 to the external terminal 117.

The first pad 113 and the second pad 115 are formed of a conductor layer (e.g., metal) that overlaps the first substrate surface 111c. The positions, shapes, and dimensions of these pads are arbitrary. For example, the two first pads 113 are lined up in the short direction of the substrate portion 111a at one end side (-D1 side) of the substrate portion 111a in the longitudinal direction. The two second pads 115 are lined up in the short direction of the substrate portion 111a at the other end side (+D1 side) of the substrate portion 111a in the longitudinal direction.

In the illustrated example, the two external electrodes 11b are located at the end of the crystal element 1 on the -D1 side, while the two second pads 115 are located on the +D1 side of the crystal element 1. In other words, the two are relatively far apart. However, the two may also be located relatively close to each other. For example, unlike the illustrated example, at least one second pad 115 may be located toward the center of the longitudinal direction of the first substrate surface 111c, adjacent to the first pad 113, or located on the +D1 side of the first pad 113.

The external terminals 117 are formed of a conductor layer (e.g., metal) that overlaps the second substrate surface 111d. The position, shape, and dimensions of the external terminals 117 are arbitrary. For example, the four external terminals 117 are located at the four corners of the second substrate surface 111d.

The positional relationship between the two external terminals 117 connected to the two first pads 113 and the two external terminals 117 connected to the two second pads 115 is arbitrary. For example, as shown in the example, the former two external terminals 117 may be located on one side (-D1 side) in the longitudinal direction of the substrate portion 111a, and the latter two external terminals 117 may be located on the other side (+D2 side) in the longitudinal direction of the substrate portion 111a. Also, for example, the former two external terminals 117 may be located diagonally to each other, and the latter two external terminals 117 may be located diagonally to each other.

The wiring conductor 119 may have various configurations. For example, the wiring conductor 119 may have a via conductor penetrating the substrate portion 111a, 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. In the illustrated example, the wiring conductor 119 is composed of only a via conductor.

The materials of the bonding material 105 and the bonding wire 121 are arbitrary. For example, the bonding material 105 is made of a conductive adhesive. The conductive adhesive is made of a thermosetting resin mixed with a metal filler. As can be understood from the fact that the position of the external electrode 11b and the position of the second pad 115 are arbitrary, the path of the bonding wire 121 is arbitrary. For example, the bonding wire 121 may pass through any of the +D1 side, -D1 side, -D2 side, and +D2 side of the crystal element 1 in the process from the top surface of the crystal element 1 to the first substrate surface 111c.

Although not specifically shown, a support member that supports the crystal element 1 may be located below the crystal element 1 at the bonding position between the crystal element 1 and the bonding wire 121. Such a support member can reduce the likelihood that the crystal element 1 will tilt too much when connecting the bonding wire 121 and the crystal element 1. The support member may be made of, for example, an insulating (or conductive) adhesive, and may or may not be in close contact with the crystal element 1.

The lid 109 is, for example, a flat plate-like member made of an insulator or 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 123 and 125 used for seam welding are shown. In an embodiment in which the lid 109 is made of metal and one of the external terminals 117 connected to the temperature-sensitive film 11 is for a reference potential, the one external terminal 117 may be connected to the lid 109 via a wiring conductor 119 (not shown).

In addition to the above examples of use, the quartz crystal element 1 may be used in a variety of ways.

For example, a crystal device (piezoelectric device) including the crystal element 1 may be an oscillator having, in addition to the crystal element 1, an integrated circuit element (IC) that applies a voltage to the crystal element 1 to generate an oscillation signal. The crystal device may also include electronic elements other than the crystal element 1 and the IC.

As can be understood from the above, the number of pads and the number of external terminals that a crystal device has are arbitrary, and the connection relationship between the multiple pads and multiple external terminals is also arbitrary. For example, in an oscillator, the crystal element 1 (extraction electrode 9 and external electrode 11b) may be electrically connected to an IC rather than to an external terminal.

In the piezoelectric device, the structure of the package that packages the crystal element 1 may be appropriately configured. 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 IC described above may be mounted in the recess on the bottom surface. The package may also be composed of a board-like base body (a base body that does not have a recess) and a cap-like lid body that is placed over the base body. For example, the piezoelectric device (package) may also have a thermostatic bath.

(4. Summary of the First Embodiment)
As described above, the piezoelectric vibration element (quartz crystal element 1) according to the embodiment has a piezoelectric body (quartz crystal blank 3), (at least) two excitation electrodes 7, (at least) two extraction electrodes 9, and a temperature-sensitive film 11. The quartz crystal blank 3 has a first region 3c and a second region 3d. The two excitation electrodes 7 overlap the surface of the first region 3c. The two extraction electrodes 9 are extracted from the two excitation electrodes 7. The temperature-sensitive film 11 has a portion that overlaps the surface of the second region 3d (the entire temperature-sensitive film 11 in the illustrated example).

Therefore, for example, as already described, the effect of making it easier to make the measured temperature follow the temperature of the quartz blank 3, the effect of miniaturizing the quartz device 101, and the effect of reducing the effect of the mass of the temperature-sensitive film 11 on the vibration of the quartz element 1 are achieved.

The crystal blank 3 may have a plate-shaped portion (the entire crystal blank 3 in the illustrated example). In a plan view of the plate-shaped portion, the first region 3c and the second region 3d may be different parts of the plate-shaped portion. The two excitation electrodes 7 may face each other with the first region 3c sandwiched between them in the thickness direction. The second region 3d may be located outside the two excitation electrodes 7 in a plan view of the plate-shaped portion.

In this case, for example, the quartz blank 3 is intended to vibrate the area (vibration part) between the two excitation electrodes 7. Therefore, by having a portion of the temperature-sensitive film 11 located in an area outside the two excitation electrodes 7, the area of the temperature-sensitive film 11 can be secured while reducing the effect that the mass of the temperature-sensitive film 11 has on the vibration of the vibration part.

The two extraction electrodes 9 may be drawn out from the two excitation electrodes 7 to the first side (-D1 side) in a planar perspective view of the plate-shaped portion (the entire crystal blank 3 in this embodiment). The temperature-sensitive film 11 may have a portion located on the first side of the two extraction electrodes 9 (the entire temperature-sensitive film 11 in the illustrated example).

In this case, for example, the temperature-sensitive film 11 is farther away from the vibration part (the region between the two excitation electrodes 7) that is intended to vibrate, compared to a configuration in which the temperature-sensitive film 11 is located in another region (this configuration is also included in the technology related to the present disclosure). In addition, between the temperature-sensitive film 11 and the vibration part, there is a region of the extraction electrode 9 that is fixed to the package 103 and whose vibration is regulated. For these reasons, the effect of the mass of the temperature-sensitive film 11 on the vibration of the vibration part is reduced. As a result, for example, the likelihood that an error will occur in the characteristics of the crystal element 1 due to an error in the mass of the temperature-sensitive film 11 is reduced. From another perspective, the degree of freedom in designing the temperature-sensitive film 11 is improved.

The piezoelectric body (quartz crystal blank 3) may have a buffer portion 13 located between the first region 3c and the second region 3d in a plan view of the plate-shaped portion (the entire quartz crystal blank 3 in this embodiment). The buffer portion 13 may include, for example, a through hole.

In this case, for example, as described above, the effect of the mass of the temperature-sensitive film 11 on the vibration of the first region 3c is reduced. As a result, for example, the design of the crystal element 1 is simplified. Also, the likelihood that an error in the characteristics of the crystal element 1 will occur due to an error in the mass of the temperature-sensitive film 11 is reduced. From another perspective, the degree of freedom in the design of the temperature-sensitive film 11 is improved.

The crystal device 101 according to this embodiment has the above-described piezoelectric vibration element (crystal element 1) and a package 103 that holds the crystal element 1. This provides various effects due to the crystal element 1 having the temperature-sensitive film 11.

The quartz crystal element 1 may be bonded to a predetermined surface (first substrate surface 111c) of the package 103 by a bonding material 105 interposed between the first substrate surface 111c and the quartz crystal element 1, facing the first substrate surface 111c. The temperature-sensitive film 11 may have a portion located on the surface (on the +D3 side) opposite the first substrate surface 111c of the quartz crystal blank 3.

In this case, for example, after the crystal element 1 is fixed to the base 107 by the bonding material 105 and before the recess R1 is closed by the lid 109, in the mode in which the excitation electrode 7 on the first surface 3a is cut for frequency adjustment, the temperature-sensitive film 11 may also be cut. This is expected to reduce the likelihood that unintended stress changes occur only in the region of the excitation electrode 7 (stress distribution becomes uneven). This effect is particularly expected in the mode in which the buffer section 13 is not provided. In addition, for example, it is possible to use the mass change of the temperature-sensitive film 11 for frequency adjustment, and it is expected that the adjustable range will be expanded. In addition, for example, in the mode in which the external electrode 11b of the temperature-sensitive film 11 is located on the first surface 3a, the bonding wire 121 can be used for electrical connection between the temperature-sensitive film 11 and the package 103. Compared to the mode in which the bonding material 127 (FIG. 7) described later is used, the effect of the electrical connection of the temperature-sensitive film 11 on the vibration of the crystal element 1 is reduced. This effect is particularly expected in configurations where the buffer section 13 is not provided.

Second Embodiment
5 and 6 are perspective views showing a quartz crystal element 201 according to the second embodiment. These figures correspond to FIGS. 1 and 2 of the first embodiment.

In the quartz crystal element 1 according to the first embodiment, the temperature-sensitive film 11 was located on the first surface 3a (the surface on the +D3 side, which faces the opposite side from the substrate portion 111a after mounting) of the quartz crystal blank 3. In contrast, in the second embodiment, the temperature-sensitive film 11 is located on the second surface 3b (the surface on the -D3 side). In other respects, the quartz crystal element 201 is basically the same as the quartz crystal element 1.

Figure 7 is a cross-sectional view showing a quartz crystal device 101A as an example of the use of the quartz crystal element 201 according to the second embodiment. This figure corresponds to Figure 6 of the first embodiment.

In the crystal device 101A, the temperature-sensitive film 11 (more specifically, the external electrode 11b shown in FIG. 6) located on the underside of the crystal element 201 is bonded to the second pad 115 of the package 103 by a conductive bonding material 127. This electrically connects the temperature-sensitive film 11 and the external terminal 117.

At least a portion of the second pad 115 faces at least a portion of the external electrode 11b. In this embodiment, the external electrode 11b is located on the -D1 side of the extraction electrode 9, and therefore the second pad 115 is located on the -D1 side of the first pad 113.

The material of the bonding material 127 is arbitrary. For example, the material of the bonding material 127 may be the same as or different from the material of the bonding material 105. The material of the bonding material 127 may be a conductive adhesive or a solder (including lead-free solder). Depending on the difference between the bonding wire 121 (FIG. 4) and the bonding material 127, the configuration of the second pad 115 and the external electrode 11b may be different between the first and second embodiments.

As described above, in the crystal element 1 of the first embodiment, the film body 11a (e.g., its functional part) may be located on the first surface 3a of the crystal blank 3, while the external electrode 11b may be located on the second surface 3b. Therefore, bonding using the bonding material 127 can also be applied to a configuration in which the film body 11a (part or all of it) is located on the first surface 3a, as in the first embodiment. Conversely, bonding using the bonding wire 121 can also be applied to a configuration in which the film body 11a (part or all of it) is located on the second surface 3b, as in the second embodiment. Furthermore, it is also possible to combine the bonding wire 121 and the bonding material 127, such as using the bonding wire 121 for one external electrode 11b and the bonding material 127 for the other external electrode 11b.

As described above, in this embodiment, the crystal element 201 also has two excitation electrodes 7 located in the first region 3c, two extraction electrodes 9 extending from the two excitation electrodes 7, and a temperature-sensitive film 11 overlapping the second region 3d. Therefore, the same effect as in the first embodiment is achieved.

The quartz crystal element 201 may be bonded to a predetermined surface (first substrate surface 111c) of the package 103 by a bonding material 105 (and/or a bonding material 127) interposed between the first substrate surface 111c and the quartz crystal element 1, facing the predetermined surface (first substrate surface 111c). The temperature-sensitive film 11 may have a portion located on the surface (second surface 3b) of the first substrate surface 111c of the quartz crystal blank 3.

In this case, for example, in a case where the excitation electrode 7 on the first surface 3a is scraped off for frequency adjustment after the crystal element 201 is mounted and before sealing with the lid 109, the likelihood that the temperature-sensitive film 11 will also be scraped off is reduced. As a result, for example, in a case where the functional portion of the temperature-sensitive film 11 (resistive film in the case of a thermistor) is exposed, the likelihood that the characteristics of the functional portion will change is reduced. From another perspective, the need to provide a protective film to cover the functional portion is reduced.

Third Embodiment
8 is a perspective view showing a quartz crystal element 301 according to the third embodiment. This figure corresponds to FIG. 1 of the first embodiment.

The quartz crystal element 301 is, in short, a combination of the first and second embodiments. That is, the temperature-sensitive film 11 has both a portion located on the first surface 3a and a portion located on the second surface 3b. In the illustrated example, the temperature-sensitive film 11 also has a portion located on the side (-D2 side surface, +D2 side surface, -D1 side surface and/or +D1 side surface) of the quartz crystal blank 3 (more specifically, the second region portion 3d) in order to connect the above two portions. Each of the two external electrodes 11b may be located on either the first surface 3a or the second surface 3b (and the side surface) of the quartz crystal blank 3. In the illustrated example, both of the two external electrodes 11b are located on the first surface 3a, as in the first embodiment.

Unlike the illustrated example, for example, the temperature sensing part 11 may not be connected between the part on the first surface 3a and the part on the second surface 3b, and two external electrodes 11b may be provided for each. Also, for example, the functional part of the film body 11a (resistive film in a thermistor) may not be connected between the part on the first surface 3a and the part on the second surface 3b, and the conductor may be connected between the part on the first surface 3a and the part on the second surface 3b, and only two external electrodes 11b may be provided. Also, for example, if a through hole is provided that penetrates the second region 3d in the thickness direction, the part on the first surface 3a and the part on the second surface 3b may be connected via the through hole (e.g., a slit).

The explanations of the first and second embodiments may be applied to this embodiment. In the temperature-sensitive film 11, the shape of the portion located on the first surface 3a and the shape of the portion located on the second surface 3b may be the same or different. From another perspective, the two may overlap in large part (e.g., 80% or more of the area of each portion) or may not overlap in large part.

In the temperature-sensitive film 11, the position, shape, and dimensions of the portion connecting the first surface 3a and the second surface 3b are also arbitrary. For example, the connection may be made on any one, two, three, or four of the four sides of the portion located on one of the first surface 3a and the second surface 3b. Also, for example, the connection may be made along the entire long side, or only along a part of the long side.

As described above, in this embodiment, the quartz crystal element 301 also has two excitation electrodes 7 located in the first region 3c, two extraction electrodes 9 extending from the two excitation electrodes 7, and a temperature-sensitive film 11 overlapping the second region 3d. Therefore, the same effect as in the first embodiment is achieved.

Fourth Embodiment
9 and 10 are perspective views showing a quartz crystal element 401 according to the fourth embodiment. These figures correspond to FIGS. 1 and 2 of the first embodiment.

In the first embodiment, the first region 3c has a configuration similar to that of a typical cantilever-shaped quartz element or a similar quartz element, and the second region 3d is an additional portion to the first region 3c. On the other hand, the quartz element 401 has a configuration in which the entire quartz element is a typical cantilever-shaped quartz element or a similar quartz element with a buffer portion 13 provided.

From another perspective, the terminal portion 9b of the extraction electrode 9 is located in the second region 403d, not the first region 403c, in the crystal blank 403. The excitation electrode 7 and the terminal portion 9b are connected by the wiring portion 9a located in the connecting portion 403e. In the illustrated example, the wiring portion 9a is located on the upper or lower surface of the connecting portion 403e. The wiring portion 9a may also be located on the side of the connecting portion 403e, etc.

The temperature-sensitive film 11 is located, for example, on the upper surface (first surface 403a, the surface opposite to the substrate portion 111a of the package 103 after mounting) of the second region 403d. In a plan view, the temperature-sensitive film 11 partially overlaps at least one (both in the illustrated example) of the two extraction electrodes 9 (e.g., terminal portion 9b) located on the lower surface (second surface 403b) of the second region 403d. In addition, the temperature-sensitive film 11 may overlap (in the illustrated example) a portion of at least one of the two extraction electrodes 9 (e.g., wiring portion 9a) located on the upper surface of the second region 403d. As described above, in the former embodiment, an insulating film may be interposed between the functional film (resistive film in the thermistor) and the extraction electrode 9.

Although not specifically shown, a part or all of the temperature-sensitive film 11 may be located on the lower surface (second surface 403b) of the second region 403d, avoiding the terminal portion 9b (or from another point of view, the bonding material 105). In this case, the second region 403d may be wider in the D2 direction and/or the -D1 direction than in the illustrated example. As will be understood from the modified example (FIG. 15) described later, the area of the second region may be secured in various shapes (in various directions).

The crystal element 401 may be mounted in the same manner as in the first or second embodiment. Specifically, the crystal element 401 may be supported in a cantilever shape by bonding two extraction electrodes 9 to the first pad 113 with a conductive bonding material 105. The temperature-sensitive film 11 may be electrically connected to the second pad 115 by a bonding wire 121. Unlike the illustrated example, in a configuration in which the external electrode 11b is located on the underside of the second region 403d, the temperature-sensitive film 11 may be electrically connected to the second pad 115 by a bonding material 127.

As described above, in this embodiment, the crystal element 401 also has two excitation electrodes 7 located in the first region 403c, two extraction electrodes 9 extending from the two excitation electrodes 7, and a temperature-sensitive film 11 overlapping the second region 403d. Therefore, the same effect as in the first embodiment is achieved.

The two extraction electrodes 9 may have a portion that overlaps at least one of the two extraction electrodes 9 in a planar perspective of the plate-shaped portion (the entire crystal blank 403 in the illustrated example). Note that the overlapping here may be a direct overlap on the first surface 403a, or an indirect overlap with the portion of the extraction electrode 9 located on the second surface 403b.

In the above case, for example, compared to a configuration in which the entire temperature-sensitive film 11 is located closer to the excitation electrode 7 than the extraction electrode 9 (or terminal portion 9b) (this configuration is also included in the technology related to the present disclosure), the temperature-sensitive film 11 has an area where it is fixed to the package 103 and vibration is restricted, and/or a portion located around that area. Therefore, the effect of the mass of the temperature-sensitive film 11 on the vibration in the excitation electrode 7 area is reduced. As a result, for example, the likelihood that an error in the characteristics of the crystal element 1 will occur due to an error in the mass of the temperature-sensitive film 11 is reduced. From another perspective, the degree of freedom in designing the temperature-sensitive film 11 is improved.

Fifth Embodiment
Fig. 11 is a perspective view showing a quartz crystal element 501 according to the fifth embodiment. This figure corresponds to Fig. 1 of the first embodiment. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11.

The quartz element 501 differs from the quartz element 1 of the first embodiment in the configuration of the quartz blank. Specifically, the quartz blank 503 of the quartz element 501 has a second region 503d that is thicker than the first region 503c. By making the second region 503d thicker, for example, the proportion of the mass per unit area of the temperature-sensitive film 11 in the mass per unit area of the quartz blank 503 is reduced. This reduces, for example, the effect of the mass of the temperature-sensitive film 11 on vibrations in the first region 503c. This effect is particularly effective in an embodiment in which the buffer section 13 is not provided.

11 and 12, as in the first embodiment, an example is shown in which the temperature-sensitive film 11 is located on the first surface 503a. Unlike the illustrated example, a part or all of the temperature-sensitive film 11 may be located on the second surface 503b (see the second and third embodiments described above). Also, as in the first embodiment, FIG. 11 and 12, as in the first embodiment, an example is shown in which the terminal portion 9b (not shown) of the extraction electrode 9 is located in the first region 503c. Unlike the illustrated example, the terminal portion 9b may be located in the second region 503d (see the fourth embodiment described above).

12, the connecting portion 503e (not shown in FIG. 11 because it is hidden by the second region 503d. In other words, the intermediate region between the first region 503c and the second region 503d) that connects the first region 503c and the second region 503d may have a thickness that gradually changes from the thickness of the first region 503c to the thickness of the second region 503d. From another perspective, the connecting portion 503e may have an inclined surface. The angle of the inclined surface may be any size, and may be determined by the angle of the crystal plane that appears due to the anisotropy of the quartz crystal with respect to etching. Although not particularly shown, the inclined surface may have a recess that extends from the relatively thin region to the relatively thick region. Such a recess may contribute, for example, to facilitating the formation of a conductor layer that spans both regions. Unlike the example shown, the thickness of part or all of the connecting portion 503e may be the same as the thickness of the first region 503c or the second region 503d.

In the illustrated example, the second region 503d is thicker than the first region 503c on both the side facing the first surface 503a (+D3 side) and the side facing the second surface 503b (-D3 side). Unlike the illustrated example, the second region 503d may be thicker only on the +D3 side or only on the -D3 side. In other words, the second region 503d may be thicker on either the substrate 111a side (-D3 side) or the side opposite the substrate 111a (+D3 side), or may be thicker on both sides. In addition, in a mode in which the second region 503d is thicker on the substrate 111a side or the side opposite the substrate 111a, the temperature-sensitive film 11 may be located on the thicker side or the side not thicker.

In an embodiment in which the second region 503d is thicker than the first region 503c on only one side in the thickness direction and the temperature-sensitive film 11 is located only on the thicker side, for example, the mass of the crystal blank 503 interposed between the first region 503c and the temperature-sensitive film 11 becomes large. As a result, for example, the effect of reducing the influence of the mass of the temperature-sensitive film 11 on the vibration of the first region 503c is improved. Conversely, in an embodiment in which the temperature-sensitive film 11 is located only on the non-thickened side, for example, the mass of the crystal blank 503 interposed between the first region 503c and the temperature-sensitive film 11 becomes small, so that the effect of making the measured temperature follow the temperature of the first region 503c is improved. In an embodiment in which the second region 503d is thicker on both sides (the +D3 side and the -D3 side) and/or the temperature-sensitive film 11 is located on both sides, for example, the above effects are harmonized.

In the illustrated example, in a configuration in which the second region 503d is thickened on both sides (the +D3 side and the -D3 side), the planar shape of the portion that is thickened on the +D3 side and the planar shape of the portion that is thickened on the -D3 side generally match, for example. However, the two may be different. Also, the amount of thickening on the +D3 side and the amount of thickening on the -D3 side may be the same or different. Note that the thickness of the second region 503d described in the embodiment is the thickness from the surface on the +D3 side to the surface on the -D3 side unless otherwise specified, and may be applied to a configuration in which the second region 503d is thickened on one or both of the +D3 side and the -D3 side.

The difference or ratio between the thickness of the second region 503d and the thickness of the first region 503c is arbitrary. For example, the thickness of the second region 503d may be 1.5 times or more, 2 times or more, 3 times or more, 5 times or more, or 10 times or more, and 20 times or less, 10 times or less, 5 times or less, or 3 times or less, relative to the thickness of the first region 503c. The above lower limit and upper limit may be combined with any combination that does not contradict. In addition, the difference between the thickness of the second region 503d and the thickness of the first region 503c may be, for example, 5 μm or more, 10 μm or more, 20 μm or more, or 30 μm or more, and may be 100 μm or less, 50 μm or more, or 30 μm or less. The above lower limit and upper limit may be combined with any combination that does not contradict.

As described above, in this embodiment, the crystal element 501 also has two excitation electrodes 7 located in the first region 503c, two extraction electrodes 9 extending from the two excitation electrodes 7, and a temperature-sensitive film 11 overlapping the second region 503d. Therefore, the same effect as in the first embodiment is achieved.

The first region 503c and the second region 503d may be different parts when the quartz crystal blank 503 is viewed in the thickness direction. The thickness of the second region 503d may be thicker than the thickness of the first region 503c.

In this case, for example, as described above, the effect of the mass of the temperature-sensitive film 11 on the vibration of the first region 503c is reduced. As a result, for example, the design of the crystal element 501 is simplified. In addition, the likelihood that an error in the characteristics of the crystal element 501 will occur due to an error in the mass of the temperature-sensitive film 11 is reduced. From another perspective, the degree of freedom in the design of the temperature-sensitive film 11 is improved.

The configuration of this embodiment, in which the second region 503d is thicker than the first region 503c, may be applied to quartz blanks having shapes other than a plate shape. The configuration of this embodiment may be combined with various planar shapes as long as the quartz blank is capable of determining thickness. For example, in a tuning fork-shaped quartz blank, the second region (e.g., the base) may be thicker than the first region (the vibrating arm extending from the base).

<Modification>
Various modified examples will be described below in the following order:
Modifications of the Planar Shape of the Buffer Section 13 (FIGS. 13(a) and 13(b))
Modifications of the cross-sectional shape of the buffer section 13 (FIGS. 14(a) and 14(b))
Modification of the second region 3d and the connecting portion 3e (FIG. 15)

(Modifications Related to Planar Shape of Buffer Section)
Fig. 13A is a plan view showing a crystal element 401A according to a modified example, and Fig. 13B is a plan view showing a crystal element 401B according to another modified example.

In these figures, the configuration of the crystal elements 401A and 401B is shown with a dimensional ratio assuming the fourth embodiment (FIGS. 9 and 10). Also, the thermosensitive film 11 is shown as being located on the first surface 403a (the surface on the +D3 side). Unlike the illustrated example, the modified example of the buffer section 13 shown here may be applied to the first to third and fifth embodiments.

In the quartz crystal element 401A shown in FIG. 13(a), the planar shape of the buffer section 13A is circular. A plurality of buffer sections 13A having the same shape and dimensions are arranged at a constant pitch in a direction (D2 direction) intersecting (e.g., perpendicular to) the direction (D1 direction) from the first region 403c to the second region 403d. From another perspective, a plurality of connecting sections 403e are arranged at a constant pitch. Unlike the illustrated example, the shapes and dimensions of the plurality of buffer sections 13A (a plurality of connecting sections 3e) do not have to be the same. The pitch of the plurality of buffer sections 13A does not have to be uniform.

The planar shape of the buffer section 13A is, in other words, not elongated, and furthermore, is a shape in which the long and short directions cannot be distinguished. Examples of such shapes include a circle, a square, and a regular polygon other than a square. From another perspective, the length of the buffer section 13A in the D2 direction may be, for example, 1/2 to 2 times the length in the D1 direction. The number of buffer sections 13A (connecting sections 403e) may be, for example, relatively large, and more specifically, may be 4 or more or 5 or more. The interval between adjacent buffer sections 13A (width of connecting sections 403e) may be, for example, 1/2 to 2 times the length of the buffer section 13A in the arrangement direction (D2 direction).

The temperature-sensitive film 11 extends over almost the entire second region 403d. From another perspective, the arrangement range of the temperature-sensitive film 11 in the D2 direction almost overlaps with the arrangement range of the multiple buffer parts 13A (multiple connecting parts 403e). For example, the length of the temperature-sensitive film 11 in the D2 direction may be 2/3 or more or 4/5 or more of the arrangement length of the multiple buffer parts 13A (the length from the +D2 side position of the buffer part 13A on the +D2 side to the -D2 side position of the buffer part 13A on the -D2 side), and may be 1.5 times or less or 1.2 times or less. The above lower limit and upper limit may be combined arbitrarily.

In such a configuration, for example, multiple connecting portions 403e are evenly positioned with respect to the temperature-sensitive film 11 extending along the edge of the first region 403c. As a result, the heat of the first region 403c can be evenly transferred to the temperature-sensitive film 11. As a result, it is expected that the effect of making the measured temperature follow the temperature of the first region 403c will be improved.

In the quartz crystal element 401B shown in FIG. 13(b), the buffer section 13B is arranged so as to avoid the geometric center of the first region 403c and/or the geometric center of the excitation electrode 7 in a direction (D2 direction) intersecting (e.g., perpendicular to) the direction (D1 direction) from the first region 403c to the second region 403d. Specifically, the two buffer sections 13B are located on both sides of the geometric center in the D2 direction. The planar shape of each buffer section 13B is arbitrary, and for example, is an elongated shape (slit-shaped) as in the embodiment.

From another perspective, the quartz crystal blank 403 has a connecting portion 403e (the central one of the three connecting portions 403e) whose position in the D2 direction overlaps with the geometric center of the first region portion 403c and/or the geometric center of the excitation electrode 7. The position of the geometric center of this central connecting portion 403e in the D2 direction may, for example, coincide with the geometric center of the first region portion 403c and/or the geometric center of the excitation electrode 7. The width of the central connecting portion 403e may be relatively wide. For example, the width of the central connecting portion 403e may be, for example, 1/2 or more or 2/3 or more of the width of the excitation electrode 7, and may be 1.2 times or less, 1 time or less, or 9/10 or less. The above lower limit and upper limit may be combined arbitrarily.

The length of the temperature-sensitive membrane 11 in the D2 direction is, for example, approximately equal to the length of the central connecting portion 403e in the D2 direction. At least one of the lengths overlaps at least a portion of the other length. For example, the former may be 2/3 or more or 4/5 or more of the latter, and may be 1.5 times or less or 1.2 times or less. The above lower and upper limits may be combined in any way.

In such a configuration, for example, heat from the area of the first region 403c that overlaps with the excitation electrode 7 is easily transmitted to the entire temperature-sensitive film 11. As a result, it is expected that the effect of making the measured temperature follow the temperature of the first region 403c is improved.

Figures 14(a) and 14(b) are cross-sectional views showing modified examples of the buffer section 13. These figures correspond to, for example, a part of Figure 4.

In these figures, the configurations of the crystal elements 1C and 1D are shown with dimensional ratios assuming the first embodiment (FIGS. 1 and 2). Also, the thermosensitive film 11 is shown as being located on the first surface 3a (the surface on the +D3 side). Unlike the illustrated example, the modified example of the buffer section 13 shown here may be applied to the second to fifth embodiments.

In the modified example shown in FIG. 14(a), the crystal blank 3 has a recess as the buffer portion 13C. In the modified example shown in FIG. 14(b), the crystal blank 3 has a protrusion as the buffer portion 13D. The explanations of the buffer portions 13, 13A, and 13B may be applied to the buffer portions 13C and 13D, unless a contradiction arises. For example, the planar shape of the buffer portions 13C and 13D may be the same as the planar shape of the buffer portion 13, 13A, or 13B. As will be understood from the modified example (FIG. 15) described later, the buffer portion 13 may extend in various directions at various positions. The cross-sectional shapes and/or dimensions of the buffer portions 13C and 13D may differ depending on the position and extension direction of these buffer portions.

In a cross section perpendicular to any direction of the buffer portion 13C (recess) in a plan view (for example, the direction in which the groove extends when the buffer portion 13C is a groove), the shape and dimensions of the buffer portion 13C are arbitrary. For example, the buffer portion 13C may be dug into the crystal blank 3 at a constant width, or may be narrower toward the +D3 side or the -D3 side. Also, for example, the cross-sectional shape of the buffer portion 13A may be a shape with a bottom surface (as in the illustrated example), or may be a shape without a bottom surface (for example, a V-groove shape). The depth (for example, maximum depth) of the buffer portion 13C may be less than 1/2, about 1/2 (as in the illustrated example), or more than 1/2 of the thickness of the crystal blank 3 (thickness at the position of the buffer portion 13C).

In a cross section perpendicular to any direction of the buffer portion 13D (convex portion) in a plan view (for example, the direction in which the protrusion extends when the buffer portion 13D is a protrusion), the shape and dimensions of the buffer portion 13D are arbitrary. For example, the buffer portion 13D may protrude with a constant width, or the width may become narrower toward the tip. The cross-sectional shape of the buffer portion 13D may be a shape with a top surface (as in the illustrated example), or a shape without a top surface (for example, a triangular shape). The height (for example, the maximum height) of the buffer portion 13D may be less than 1/2, about 1/2 (as in the illustrated example), or more than 1/2 of the thickness of the quartz blank 3 (the thickness at the position of the buffer portion 13D, or the minimum thickness or maximum thickness).

The relationship between the surface on which the temperature-sensitive film 11 is located and the surface on which the buffer portion 13C or 13D is located is arbitrary. For example, as in the illustrated example, in a configuration in which the temperature-sensitive film 11 is located on only one of the first surface 3a and the second surface 3b, the buffer portion 13C or 13D may be located on the same surface as the surface on which the temperature-sensitive film 11 is located (the first surface 3a in the illustrated example), or on the opposite surface (the second surface 3b in the illustrated example), or on both surfaces. Also, for example, in a configuration in which the temperature-sensitive film 11 is located on both the first surface 3a and the second surface 3b, the buffer portion 13C or 13D may be located on only one surface, or on both surfaces.

Although not specifically shown, the buffer sections 13 (13A and 13B), 13C and 13D may be combined with each other. For example, different types of buffer sections may be provided at different positions in a plan view. Also, for example, buffer section 13C may be provided on one of the first surface 3a and the second surface 3b, and buffer section 13D may be provided on the other surface. As described above, the buffer section may include at least one of a recess on the first surface 3a, a recess on the second surface 3b, a convex portion on the first surface 3a, a convex portion on the second surface 3b, and a through hole.

(Modifications of the second region and the connecting portion)
FIG. 15 is a table showing various modified examples regarding the positions, shapes and dimensions of the second region 3d and the connecting portion 3e.

For convenience, the symbols in the first embodiment are used in this explanation. However, the modifications here may also be applied to the second to fifth embodiments.

In the crystal element 1 according to the embodiment, the second region 3d is shaped to extend along one edge of the first region 3c (or the excitation electrode 7), which can be conceptualized as having four edges (or, from another point of view, adjacent to one edge). However, the second region 3d may be shaped to extend along two or more edges. The second region 3d may also be shaped to extend along any of the four edges. Furthermore, the number of connecting portions 3e is arbitrary. FIG. 15 is a diagram illustrating some of the modified examples relating to the position and shape of such second region 3d and the position and shape of connecting portion 3e.

For convenience, in the following description, the portion of the second region 3d that extends along one edge of the first region 3c may be referred to as a segment 3s. In the various modified examples shown in FIG. 15, the description of the second region in the various embodiments described above may be applied to one segment 3s or to the entire second region 3d having two or more segments 3s, unless a contradiction arises.

As can be seen from the symbols in the lower left of the figure, each square shows a schematic representation of a quartz blank 3. In addition, to make the first area 3c, the second area 3d, and the connecting area 3e easier to see, the second area 3d is hatched with diagonal lines, and the connecting area 3e is hatched with polka dots.

The four columns correspond to variants with different numbers of segments 3s. The top cells (cells with the numbers "1", "2", "3" and "4") show the number of segments 3s in each column. The rows (excluding the top cell) correspond to variants with different numbers of connecting parts 3e. Within one cell, variants in which the same number of connecting parts 3e are in different positions are shown.

In the first row, the second region 3d has one segment 3s. The position of the segment 3s may be on the short side or long side of the first region 3c. In addition, the short side of the first region 3c to which the segment 3s is adjacent is not limited to the short side on the extraction electrode 9 side relative to the excitation electrode 7, but may be the short side on the opposite side of the extraction electrode 9 relative to the excitation electrode 7.

In the second row, the second region 3d has two segments 3s. More specifically, in the illustrated example, the two segments 3s are aligned along one short side and one long side, and are connected to each other. That is, the second region 3d is L-shaped. Unlike the illustrated example, it is also possible to not connect multiple segments 3s (here, two). In this case, for example, the two segments 3s may be aligned along the two long sides or along the two short sides.

In the third row, an embodiment is shown in which the second region 3d has three segments 3s. More specifically, in the illustrated example, the three segments 3s are aligned along one long side and two short sides of the first region 3c and are connected to each other. That is, the second region 3d is U-shaped. Note that, unlike the illustrated example, the U-shaped second region 3d may be aligned along one short side and two long sides.

In the fourth row, the second region 3d has four segments 3s. From another perspective, the second region 3d has a ring shape (frame shape) surrounding the first region 3c. As mentioned above, it is also possible for some of the segments 3s to be unconnected. For example, the second region 3d may be C-shaped with a broken portion.

The two or more segments 3s may have the same configuration as each other, or may have different configurations. For example, the segment 3s extending in the D2 direction and the segment 3s extending in the D1 direction may have the same width as each other, or may have different widths from each other. Also, for example, the segment 3s extending in the D2 direction and the segment 3s extending in the D1 direction may both be straight, or one may be straight and the other may be curved.

The first row shows an embodiment in which the first region 3c and the second region 3d are directly connected. That is, the quartz crystal blank 3 does not have a connecting portion 3e (or, from another point of view, a buffer portion 13). In this case, the first region 3c and the second region 3d may be distinguished, for example, by the presence or absence of a temperature-sensitive film 11 and/or by a difference in thickness (see the fifth embodiment in FIG. 11).

The second row shows an embodiment in which there is one connecting portion 3e. The connecting portion 3e may be located in the center of the segment 3s in the longitudinal direction of the segment 3s, or at an end of the segment 3s. The second to fourth columns show an embodiment in which the connecting portion 3e is located on the short side of the first region 3c. However, the connecting portion 3e may also be located on the long side of the first region 3c.

The third row shows an embodiment in which the number of connecting parts 3e is two. The two connecting parts 3e may be connected to the same segment 3s, or may be connected to different segments 3s. As described above, the side to which the connecting parts 3e are connected may be either a short side or a long side.

The temperature-sensitive film 11 may extend over substantially the entire area (e.g., 80% or more of the area) of the second region 3d of various shapes on at least one of the first surface 403a and the second surface 403b. The above description of the second region 3d may be applied to the temperature-sensitive film 11 as long as no contradiction arises. For example, the planar shape of the temperature-sensitive film 11 may be regarded as having one or more segments. It is also possible to make the number of segments of the temperature-sensitive film 11 different from the number of segments 3s on one of the first surface 403a and the second surface 403b.

In a configuration in which the thermosensitive film 11 has two or more segments, the two external electrodes 11b may be located, for example, in one segment, or in different segments 3s. For example, the two external electrodes 11b may be located at both ends of the entire thermosensitive film 11 in an L-shaped or U-shaped thermosensitive film 11.

As described above, the shape of the first region 3c and/or the excitation electrode 7 may be various shapes, such as a circular shape. In other words, the shape of the first region 3c and/or the excitation electrode 7 is not necessarily a shape that can be conceived of as four edges (not limited to straight lines). Furthermore, it is not necessarily possible to conceive of a segment 3s for the second region 3d. Therefore, we will describe modified lengths of the second region 3d using a concept different from the concept of the segment 3s.

The second region 3d may be, for example, within an angular range around the geometric center of the excitation electrode 7 or the quartz crystal blank 3, within a range of 90° or less, 90° or more to 180° or less, 180° or more to 270° or less, or 270° or more to 360° or less. As can be understood from the description of the segment 3s, the direction of the angular range in which the second region 3d is located is arbitrary. For example, the direction of the center of the angular range in which the second region 3d is located may be the +D1 direction, the -D1 direction, the +D2 direction, or the -D2 direction.

In the above embodiments and modifications, the crystal elements 1, 201, 301, 401, 501, 401A, 401B, 1C, and 1D are each an example of a piezoelectric vibration element. The crystal devices 101 and 101A are each an example of a piezoelectric device. The crystal blanks 3, 403, and 503 are each an example of a piezoelectric body. The first substrate surface 111c is an example of a predetermined surface of a package.

The technology disclosed herein is not limited to the above embodiments and modifications, and may be implemented in various ways.

The piezoelectric body of the piezoelectric vibration element is not limited to quartz. For example, the piezoelectric body may be another single crystal, or may be made of polycrystal (e.g., ceramic). Quartz with an appropriate dopant added may be considered a type of quartz.

The piezoelectric vibration element is not limited to one intended to generate an oscillation signal. For example, the piezoelectric vibration element may be a piezoelectric gyro sensor.

The piezoelectric vibration element may be mounted in a package or the like in various ways. For example, the piezoelectric vibration element may be supported at both ends by two conductive bonding materials bonded to two extraction electrodes. Also, for example, the piezoelectric vibration element may have a conductive bonding material bonded to one extraction electrode, and a bonding wire bonded to one extraction electrode. Also, an insulating bonding material (which can be conductive) bonded to an area different from the area of the extraction electrode may be used as a bonding material for supporting one or both ends of the piezoelectric vibration element.

1...quartz crystal element (piezoelectric vibration element), 3...quartz crystal blank (piezoelectric body), 3c...first region, 3d...second region, 7...excitation electrode, 9...extraction electrode, 11...temperature-sensitive film, 101...quartz crystal device (piezoelectric device).

Claims (7)

a piezoelectric body having a first region and a second region;
Two excitation electrodes having portions overlapping with a surface of the first region;
Two extraction electrodes extending from the two excitation electrodes;
a temperature-sensitive film having a portion overlapping a surface of the second region;
It has
The piezoelectric body has a plate-shaped portion,
In a plan view of the plate-shaped portion, the first region and the second region are different portions of the plate-shaped portion,
The two excitation electrodes face each other across the first region in a thickness direction,
the second region is located outside the two excitation electrodes in a plan view of the plate-shaped portion,
the two extraction electrodes are extracted from the two excitation electrodes to a first side in a planar perspective view of the plate-shaped portion,
The temperature-sensitive film has a portion located closer to the first side than the two extraction electrodes.
Piezoelectric vibration element. a piezoelectric body having a first region and a second region;
Two excitation electrodes having portions overlapping with a surface of the first region;
Two extraction electrodes extending from the two excitation electrodes;
a temperature-sensitive film having a portion overlapping a surface of the second region;
It has
The piezoelectric body has a plate-shaped portion,
In a plan view of the plate-shaped portion, the first region and the second region are different portions of the plate-shaped portion,
The two excitation electrodes face each other across the first region in a thickness direction,
the second region is located outside the two excitation electrodes in a plan view of the plate-shaped portion,
The plate-shaped portion is
a first surface and a second surface facing opposite sides in a thickness direction;
a buffer portion located between the first region and the second region in a plan view of the plate-shaped portion,
The buffer portion includes at least one of a recess in the first surface, a recess in the second surface, a protrusion in the first surface, a protrusion in the second surface, and a through hole.
Piezoelectric vibration element. The piezoelectric vibration element according to claim 1 , wherein the temperature-sensitive film has a portion that overlaps with at least one of the two extraction electrodes in a plan view of the plate-shaped portion. the first region and the second region are different regions when viewed in a thickness direction of the piezoelectric body,
The piezoelectric vibration element according to claim 1 , wherein the second region is thicker than the first region. The piezoelectric vibration element according to any one of claims 1 to 4 ,
A package that holds the piezoelectric vibration element;
A piezoelectric device having a the piezoelectric vibration element is bonded to a predetermined surface of the package by a bonding material interposed between the predetermined surface and the piezoelectric vibration element in a state where the piezoelectric vibration element faces the predetermined surface,
The piezoelectric device according to claim 5 , wherein the temperature-sensitive film has a portion located on a surface of the piezoelectric body opposite to the predetermined surface. the piezoelectric vibration element is bonded to a predetermined surface of the package by a bonding material interposed between the predetermined surface and the piezoelectric vibration element in a state where the piezoelectric vibration element faces the predetermined surface,
The piezoelectric device according to claim 5 , wherein the temperature-sensitive film has a portion located on a surface of the piezoelectric body on the side of the predetermined surface.

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