Piezoelectric vibration element and piezoelectric device

Abstract

To provide a piezoelectric vibration element that facilitates making a measurement temperature approach the temperature of a piezoelectric body.SOLUTION: A crystal element 1 has a crystal blank 3, two excitation electrodes 7, two extraction electrodes 9, and a temperature-sensitive film 11. The two excitation electrodes 7 overlap a surface of the crystal blank 3. The two extraction electrodes 9 are drawn out from the two excitation electrodes 7, respectively. The temperature-sensitive film 11 has a portion overlapping a region different from a region where the two excitation electrodes 7 overlap with each other, of the surface of the crystal blank 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Piezoelectric devices such as quartz crystal resonators and quartz crystal oscillators are known (see, for example, the following patent documents). Such piezoelectric devices 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 overlapping the piezoelectric body, and two extraction electrodes extending from the two excitation electrodes. The two extraction electrodes contribute to mounting the piezoelectric vibration element on the package by, for example, being joined to pads on the package with a conductive bonding material.

[0003] As such a piezoelectric device, there is known one having a temperature-sensing element such as a thermistor. The temperature detected by the temperature-sensing element is used to compensate for changes in the characteristics of the piezoelectric vibration element caused by temperature changes, for example.

[0004] The temperature-sensing element is mounted in a package. For example, in Patent Document 1, the package has a first recess and a second recess that opens to 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-sensing element is a chip-type component, and is housed in the second recess and mounted on the bottom surface of the second recess. Specifically, two terminals of the temperature-sensing element and two pads located on the bottom surface of the second recess are joined by a conductive bonding material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-211340 A Summary of the Invention [Problem to be solved by the invention]

[0006] For example, it is anticipated that a piezoelectric vibration element and a piezoelectric device will be provided that can easily bring the measurement temperature closer to the temperature of the piezoelectric body. [Means for solving the problem]

[0007] A piezoelectric vibration element according to one embodiment of the present disclosure comprises a piezoelectric body, two excitation electrodes overlapping a surface of the piezoelectric body, two extraction electrodes extending from the two excitation electrodes, and a temperature-sensitive membrane having a portion overlapping an area of ​​the surface of the piezoelectric body different from the area where the two excitation electrodes overlap.

[0008] A piezoelectric device according to one aspect of the present disclosure includes the above-described piezoelectric vibration element and a package that holds the piezoelectric vibration element. Effect of the Invention

[0009] According to the above configuration, for example, it is easy to bring the measured temperature closer to the temperature of the piezoelectric body. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing a quartz crystal element according to a first embodiment. [Diagram 2] 2 is another perspective view showing the quartz crystal element of FIG. 1. [Diagram 3] 3(a) and 3(b) are plan views showing a quartz crystal element according to a modified example and another modified example. [Figure 4] 1 is a diagram showing quartz crystal elements according to various modified examples. [Diagram 5] FIG. 1 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. [Figure 6] 6 is a cross-sectional view taken along line VI-VI in FIG. 5 . [Figure 7] FIG. 11 is a perspective view showing a quartz crystal element according to a second embodiment. [Figure 8]8 is another perspective view showing the quartz crystal element of FIG. 7. [Figure 9] FIG. 11 is a cross-sectional view of a quartz crystal device as an example of use of the quartz crystal element according to the second embodiment. [Figure 10] FIG. 11 is a perspective view showing a quartz crystal element according to a third embodiment. [Figure 11] FIG. 13 is a perspective view showing a quartz crystal element according to a fourth embodiment. [Figure 12] FIG. 12(a) is a cross-sectional view taken along line XII-XII in FIG. 11, and FIG. 12(b) and FIG. 12(c) are cross-sectional views showing modified examples of the buffer section. [Figure 13] FIG. 13 is a perspective view showing a quartz crystal element according to a fifth embodiment. [Figure 14] 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment according to 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 do not match either. In addition, illustration 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 shown in the drawings, and that features such as shapes and dimensional ratios may be extracted from the drawings.

[0012] For convenience, the drawings may include a Cartesian coordinate system D1-D2-D3. In the piezoelectric vibration element and the piezoelectric device according to the embodiment, either direction may be the up-down direction or the horizontal direction. However, for convenience, the +D3 side may be expressed as the upside. In addition, a plan view or a plan perspective view refers to a view parallel to the D3 direction, unless otherwise specified.

[0013] In the explanation of the aspects (embodiments and variants) 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 or the like arises. In multiple aspects, corresponding components may be given the same symbols for convenience, even if there are differences.

[0014] The term "side" referring to an edge of a planar shape generally refers to an edge of a polygon (in other words, a straight line), but in the description of the embodiments, for convenience, it may be used for an 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 a side of a rectangle, but in the description of the embodiments, for convenience, it may be used for an edge other than a rectangle. "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 for a relationship in which the distance between lines that do not have to be straight lines (for example, curved lines) is constant.

[0015] 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, etc. The same applies to polygons other than a rectangle.

[0016] 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 the first embodiment. Fig. 2 is a perspective view of the crystal element 1 seen from the opposite side to that in Fig. 1.

[0017] 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 whose signal strength (for example, voltage and / or current) oscillates at a certain frequency. In other words, the crystal element 1 is included, for example, in a crystal resonator or crystal oscillator. The frequency of the oscillation signal is arbitrary.

[0018] The crystal element 1 has, for example, a crystal blank 3 (one 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) overlapping the 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 leading out from the excitation electrode 7. That is, the crystal element 1 has a pair of excitation electrodes 7 and a pair of extraction electrodes 9 connected to the pair of excitation electrodes 7.

[0019] The pair of extraction electrodes 9 contribute to the mounting of the crystal element 1. Specifically, for example, as shown in FIG. 6 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 (e.g., a circuit board) other than the package 103, but for convenience, the description of the embodiment may be given on the assumption that it 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.

[0020] As shown in FIG. 1, the quartz crystal element 1 further has a temperature-sensitive film 11. The temperature-sensitive film 11 is an element for measuring temperature, and is formed, for example, of a thin-film thermistor. The temperature-sensitive film 11 has, for example, a portion that overlaps an area of ​​the quartz crystal blank 3 where the pair of excitation electrodes 7 do not overlap (an area different from the area where the pair of excitation electrodes 7 overlap). In the example shown, the entire temperature-sensitive film 11 overlaps the area where the pair of excitation electrodes 7 are not arranged. The temperature measured by the temperature-sensitive film 11 is used, for example, to compensate for changes in the characteristics of the quartz crystal element 1 (quartz crystal blank 3) caused by temperature changes.

[0021] 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, as 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.

[0022] 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. Main body of the crystal element 1 (excluding the temperature-sensitive film 11. Figures 1 and 2) 1.1. Overview of the main body of the crystal element 1 1.2. Examples of shapes, dimensions and materials of components of the body of the crystal element 1 2. Temperature-sensitive membrane 11 (Figure 1) 2.1. Overview of the composition of the thermosensitive membrane 11 2.2. Structure of the temperature-sensitive film 11 and its correspondence to the drawings 2.3. Position, shape and dimensions of the temperature-sensitive membrane 11 2.4. Position, shape and dimensions of external electrode 11b (described later) 3. Modifications of the position, shape and dimensions of the temperature-sensitive film 11 (FIGS. 3(a), 3(b) and 4) 4. Example of use of crystal element 1 (Figs. 5 and 6) 5. Summary of the First Embodiment

[0023] (1. Crystal element body (parts other than the temperature-sensitive film)) (1.1. Overview of the main body structure 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 (principal 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.

[0024] 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 crystal element 1 is supported by the package 103 in a cantilever shape, for example.

[0025] 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 extracted from the two excitation electrodes.

[0026] As can be seen from the above examples, the shape of the quartz crystal element (quartz crystal blank) is not limited to a plate shape, and may be various shapes. For example, a tuning fork-shaped quartz crystal blank has a base and a pair of vibration arms extending from the base in parallel to each other. 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. Two extraction electrodes are located, for example, on the base and / or the mounting arms extending from the base, and are bonded to the package 103 by a bonding material 105.

[0027] The crystal elements of various shapes (including plate shapes) may be, for example, thin overall, and 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 in the package 103, for example, so as to face a first substrate surface 111c (in other words, a predetermined surface) of the package 103, which will be described later. In this case, the part (vibration part) excited by the excitation electrode may be supported in a cantilever shape, as in the illustrated example.

[0028] As described above, in the embodiment in which the quartz crystal element is mounted in the package 103 so as to face the first substrate surface 111c, the quartz crystal element may or may not be configured so that either the surface on the +D3 side (first surface 3a) or the surface on the -D3 side (second surface 3b) can face the first substrate surface 111c in the entirety taking into consideration the configuration of the temperature-sensitive film 11. For example, the quartz crystal element may or may not be configured so as to be rotationally symmetrical by 180° with respect to an unillustrated axis of symmetry (for example, a center line parallel to the D1 direction in the illustrated example) perpendicular to the thickness direction.

[0029] In the description of this embodiment, for convenience, unless otherwise specified, it is assumed that the quartz crystal element 1 is an AT-cut type and / or the quartz crystal blank 3 is a quartz crystal plate. In addition, in the description of this embodiment, a mode in which the second surface 3b of the first surface 3a and the second surface 3b is assumed to be the surface facing the first substrate surface 111c is mainly taken as an example.

[0030] Furthermore, the quartz blank 3 may have inclined surfaces (or, from another point of view, crystal planes) on the side surfaces, etc., due to the anisotropy of the 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).

[0031] (1, 2. Examples of shapes, dimensions and materials of components of the main body of a quartz 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.

[0032] 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 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, or may not be configured so (illustrated example). In other words, these shapes may or may not be 180° rotationally symmetric with respect to an unillustrated axis of symmetry (e.g., a center line parallel to the D1 direction) perpendicular to the thickness 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.

[0033] For example, the planar shape of the quartz-crystal blank 3 may be rectangular (as shown in the example), circular, elliptical, or a polygonal shape other than a rectangle. The planar shape of the quartz-crystal blank 3 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 quartz-crystal blank 3 may also be a shape that has a protrusion or notch in part. For example, the planar shape of the quartz-crystal blank 3 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 a shape in which such a distinction cannot be made.

[0034] Also, for example, the thickness of the crystal blank 3 may be constant (as in the illustrated example) or may not be constant. Examples of the latter, not specifically illustrated, include the following: A so-called mesa type in which the central region (mesa portion) that overlaps with a pair of excitation electrodes 7 and is excited 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 overlaps with a pair of excitation electrodes 7 and is excited is thinner than the peripheral region. A type having a vibrating portion that overlaps with a pair of excitation electrodes 7 and is excited, and a fixed portion adjacent to a part of the edge of the vibrating portion (for example, one side, two sides, or three sides), that is thicker than the vibrating 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 peripheral edge.

[0035] Also, for example, the planar shape of the excitation electrode 7 may be similar to the planar shape of the crystal blank 3 (or the planar shape of the mesa portion, inverted mesa portion, or vibrating portion described above; the same applies below in this paragraph) (as in the illustrated example), or it may not be. The former may be, for example, a configuration in which the planar shape of the crystal blank 3-the planar shape of the excitation electrode 7 is rectangular-rectangular, circular-circular, or elliptical-elliptical. The latter may be, for example, a configuration in which the planar shape of the crystal blank 3-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 crystal blank 3, the above-mentioned explanation of the planar shape of the crystal blank 3 may be applied to the planar shape of the excitation electrode 7, as long as no contradiction occurs.

[0036] 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 bonded 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 bonding 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.

[0037] The position, shape, and dimensions of the wiring portion 9a and the terminal portion 9b are arbitrary. For example, in a mode in which the crystal element 1 is supported in a cantilever shape at one end in a predetermined direction (here, the D1 direction) as in the illustrated example, 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 a first side (here, the -D1 side) in a predetermined direction. In addition, the terminal portion 9b may be located at an end of the first side (-D1 side) of at least one of the upper surface and the lower surface. Whether or not it is located at an end may be determined rationally. For example, if the -D1 side edge of terminal portion 9b coincides with the -D1 side edge of at least one of the upper and lower surfaces, or is close to the -D1 side edge of at least one of the upper and lower surfaces at a distance less than half the D1 direction length of terminal portion 9b, terminal portion 9b may be considered to be located at the end.

[0038] 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×n / t basically holds. Here, f is the frequency (MHz), n is the order of vibration utilized, and t (mm) is the thickness. The crystal element 1 may utilize either the fundamental mode or the overtone mode.

[0039] Below are examples of the dimensional ranges of the quartz crystal element 1 (or quartz crystal blank 3). The length of the quartz crystal element 1 in the longitudinal direction (D1 direction) may be 500 μm or more and 1500 μm or less. The length of the quartz crystal element 1 in the lateral 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 dimensional ranges assuming a relatively small AT-cut type quartz crystal element 1, but may be referred to as examples of dimensions of various other quartz crystal elements.

[0040] The material of the conductive pattern 5 may be, for example, a metal. Examples of the metal include nickel (Ni), chromium (Cr), titanium (Ti), gold (Au), or silver (Ag), or an alloy containing at least one of these as a main component. The conductive pattern 5 may be configured with one conductive layer made of a single material, or may be configured by laminating multiple conductive layers made of different materials. The conductive pattern 5 may have the same material composition over its entire area, or may have different material composition depending on the region.

[0041] 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-type crystal element, the number of excitation electrodes is not limited to two, and may be three or more. However, two or more excitation electrodes having 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 surfaces 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 electrodes may include wiring portions that extend in more complicated paths.

[0042] (2.Thermosensitive membrane) (2.1. Overview of the thermosensitive membrane structure) 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. In the description of the embodiment, for convenience, the temperature-sensitive film 11 may be expressed as a thermistor, without special mention.

[0043] 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 formation 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.

[0044] Although not specifically shown, a case in which the temperature-sensitive film 11 is a thermistor will be taken as an example, and a description will be given of the fact that the specific configuration may take various forms.

[0045] The thermistor has, as a basic component, a resistive film whose resistance value changes with temperature, for example. 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 plan view, or the material composition may differ depending on the region.

[0046] 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 through an insulating film. The resistive film may have a portion that overlaps with the conductor pattern 5 (e.g., the extraction electrode 9) through 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 with the conductor pattern 5. The insulating film has a resistivity higher than that of the resistive film, for example.

[0047] The insulating film may be made of any material, for example, inorganic material, organic material, or a combination of both. Examples of inorganic materials include silicon dioxide (SiO2) and silicon nitride (Si3N4). Examples of organic materials include various resins (e.g., epoxy resin or silicone resin). The insulating film may have 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 over its entirety in a plan view, or may have different material composition depending on the region.

[0048] The resistive film may be exposed to the space formed by the package 103 (from another perspective, the inside of 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 explanation of the material of the insulating film in the previous paragraph may be applied to the coating film.

[0049] A voltage may be applied to the resistive film by a pair of application electrodes having 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.

[0050] 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 or different from at least a part of the material of the conductor pattern 5. 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 conductors described later.

[0051] (2.2. Structure of the temperature-sensitive film and its correspondence with 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 covering film, and an application electrode). In FIG. 1 (and other drawings), the configuration of the temperature-sensitive film 11 is shown as follows.

[0052] 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 via, for example, the pair of external electrodes 11b. From another perspective, the film body 11a outputs a signal having an intensity according to temperature from at least one of the pair of external electrodes 11b.

[0053] 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 covering film, an application electrode, and / or a relay conductor as described in the next paragraph that overlaps the functional part.

[0054] 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, having a part overlapping with the application electrode, or may be indirectly connected to the application electrode via a relay conductor (for example, a conductor layer different from both the application electrode and the external electrode 11b).

[0055] From another point of view, the pair of external electrodes 11b may be understood as being shown in their entirety or as being shown 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 with a coating film and is exposed from the coating film. The part may be understood as a part of the pair of external electrodes 11b that contributes to connection with the package 103 that has been extracted and shown (other parts of the pair of external electrodes 11b are also exposed, but are not shown in the drawing).

[0056] To give a specific example, as described above, the temperature-sensitive film 11 may have a pair of application electrodes overlapping the functional part on both sides in a predetermined direction (for example, a direction in which the functional part (resistive film) extends) in a plan view. 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 directly or indirectly connected to the pair of application electrodes.

[0057] Also, for example, as described above, the temperature-sensitive film 11 may have a pair of application electrodes sandwiching the resistive film in the thickness direction. In this case, the pair of external electrodes 11b shown in the figure may be parts (exposed parts or extracted parts) of the pair of application electrodes, 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 an end of one application electrode in a plan view and an end of the other application electrode in a plan view.

[0058] Also, 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. Also, the pair of terminals may be, for example, directly or indirectly connected to the pair of bus bars.

[0059] 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 a plurality of electrode fingers extend in the lateral direction. In an embodiment in which the temperature-sensitive film 11 has a plurality of first shapes, a pair of comb-tooth electrodes may be provided for each first shape.

[0060] (2.3. Position, shape and dimensions of the temperature-sensitive membrane) The position, shape and dimensions of the temperature-sensitive film 11 are arbitrary. The description of the position, shape and dimensions of the temperature-sensitive 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 case of a thermistor), and are the position, shape and dimensions of the functional part and the other parts as a whole in an embodiment in which the film body 11a includes other parts (insulating film, covering film, application electrode and / or relay conductor). However, the description of the position, shape and dimensions of the temperature-sensitive 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.

[0061] The temperature-sensitive film 11 is located, for example, only in the area of ​​the surface of the crystal blank 3 where the pair of excitation electrodes 7 (and further the pair of conductor patterns 5) are not arranged. Therefore, the position, shape and dimensions of the temperature-sensitive film 11 are restricted by the position, shape and dimensions of the area where the pair of excitation electrodes 7 (and further the pair of conductor patterns 5) are not arranged. However, the temperature-sensitive film 11 may have a portion that overlaps with a part (e.g., an edge portion) or the whole of the pair of excitation electrodes 7. In the following description of the position, shape and dimensions of the temperature-sensitive film 11, a case where the temperature-sensitive film 11 does not overlap with the pair of excitation electrodes 7 (or the pair of conductor patterns 5) is basically taken as an example. Note that the following description may be applied to a case where the temperature-sensitive film 11 has a portion that overlaps with the pair of excitation electrodes 7, unless a contradiction occurs.

[0062] 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). More specifically, the temperature-sensitive film 11 is located, in a plan view, between the outer periphery of the pair of excitation electrodes 7 (or the excitation electrodes 7 on the top surface) and the outer periphery of the crystal blank 3. The temperature-sensitive film 11 is also located on the opposite side (+D1 side) of the pair of excitation electrodes 7 to the pair of extraction electrodes 9.

[0063] The planar shape of the temperature-sensitive film 11 is, for example, a shape that extends along the edges (one side) of a pair of excitation electrodes 7 (more specifically, the excitation electrodes 7 on the upper surface side) and / or the edges (one side) of the crystal blank 3. That is, in the temperature-sensitive film 11, the length in the direction along the edges of the excitation electrodes 7 and / or the edges of the crystal blank 3 (here, the D2 direction) is longer than the width (the length in the direction perpendicular to the edges; here, the length in the D1 direction). The ratio of the length to the width is arbitrary. For example, the length may be two or more times, three or more times, or four or more times the width. Of course, the temperature-sensitive film 11 does not have to have an elongated shape (long shape), and may even have a shape in which the longitudinal direction and the lateral direction cannot be distinguished.

[0064] The planar shape of the temperature-sensitive film 11 is, for example, a rectangular shape (more specifically, a rectangle not including a square). From another perspective, in the temperature-sensitive film 11, the edge (long side) on the excitation electrode 7 side (here, the -D1 side) and the edge (long side) on the opposite side to the excitation electrode 7 (here, the +D1 side) are straight lines parallel to each other. From another perspective, the shape of the temperature-sensitive film 11 has a constant width (a tolerance may exist) over almost the entire length (for example, 80% or more of the length).

[0065] However, unlike the illustrated example, the planar shape of the temperature-sensitive film 11 may not be rectangular. For example, the planar shape of the temperature-sensitive film 11 may be polygonal, elliptical, or rectangular with the short side curved. As can be understood from the above description that the shape of the temperature-sensitive film 11 does not have to be elongated, the planar shape of the temperature-sensitive film 11 may be, for example, square or circular. From another perspective, the edge of the +D1 side and / or the edge of the -D1 side of the temperature-sensitive film 11 may be curved, or may have a bent portion, a curved portion, and / or a stepped portion. From yet another perspective, the width of the temperature-sensitive film 11 may change depending on the position in the length direction.

[0066] From another perspective, the planar shape of the temperature-sensitive film 11 is such that at least one (both in the illustrated example) of the edge on the excitation electrode 7 side (-D1 side) and the edge on the opposite side (+D1 side) to the excitation electrode 7 is parallel to at least one (both in the illustrated example) of the edge of the excitation electrode 7 and the edge of the crystal blank 3. From yet another perspective, the planar shape of the temperature-sensitive film 11 is such that the center line of the temperature-sensitive film 11 is parallel to at least one (both in the illustrated example) of the edge of the excitation electrode 7 and the edge of the crystal blank 3.

[0067] As described above, the planar shape of the excitation electrode 7 and the crystal blank 3 is not limited to a rectangular shape, and may be various. In this case, the shape described in the previous paragraph may be established. For example, the temperature-sensitive film 11 may have a curved edge (and / or a curved center line) parallel to the curved edge of the excitation electrode 7 and / or the curved edge of the crystal blank 3. Conversely, regardless of whether the planar shape of the excitation electrode 7 and the crystal blank 3 is rectangular, some or all of the shapes described in the previous paragraph may not be established. For example, in a mode in which the planar shape of the excitation electrode 7 and the crystal blank 3 is rectangular, the temperature-sensitive film 11 may be elliptical, or in a mode in which the planar shape of the excitation electrode 7 and / or the crystal blank 3 is elliptical, the temperature-sensitive film 11 may be rectangular.

[0068] The length of the temperature-sensitive film 11 (here, the length in the D2 direction) is arbitrary. For example, assume that the planar shape of the crystal blank 3 is a shape that can be conceptualized as two first edges (e.g., a pair of long sides) facing each other and two second edges (e.g., a pair of short sides) connecting the two first edges. The temperature-sensitive film 11 has a first portion that extends along one of the edges (the first edge or the second edge, referred to as the "adjacent edge" in this paragraph and the next paragraph). In this case, the length of the first portion may be, for example, 1 / 2 or more, 2 / 3 or more, 3 / 4 or more, or 1 time the length of the adjacent edge. There is no particular upper limit as long as the first portion fits within the crystal blank 3.

[0069] In the preceding paragraph, the term "quartz blank 3" may be replaced with the term "excitation electrode 7". However, the term "1 time" in the explanation of the lower limit in the preceding paragraph is replaced with the term "1 time or more". Also, in the preceding paragraph, the "length of the adjacent edge" may be replaced with the "maximum length of the quartz blank 3 in the direction in which the adjacent edge and / or the first portion extend". In this case, it is not necessary to conceive of four edges. The length of the temperature-sensitive film 11 may be, for example, the length on the center line of the temperature-sensitive film 11 or the maximum length if the planar shape of the temperature-sensitive film 11 is not rectangular.

[0070] In the illustrated example, the temperature-sensitive film 11 extends over almost the entire side of the +D1 side of the crystal blank 3. Therefore, the position of the geometric center of the temperature-sensitive film 11 in the direction in which the temperature-sensitive film 11 extends (here, the D2 direction) is almost the same as the position of the geometric center of the crystal blank 3 and / or the excitation electrode 7. For example, the deviation in the D2 direction between the two is 1 / 5 or less of the maximum length in the D2 direction of the smaller of the compared members. This relationship between the geometric centers may also be established when the length of the temperature-sensitive film 11 is the various lengths described above. Conversely, unlike the illustrated example, the geometric center of the temperature-sensitive film 11 and the geometric center of the crystal blank 3 and / or the excitation electrode 7 may be offset in the direction in which the temperature-sensitive film 11 extends. Furthermore, the entire temperature-sensitive film 11 may be located on one side of the geometric center of the crystal blank 3 and / or the excitation electrode 7 in the direction in which the temperature-sensitive film 11 extends.

[0071] The width of the temperature-sensitive film 11 (here, the length in the D1 direction) is arbitrary. For example, as shown in the figure, the distance between the edge of the excitation electrode 7 and the edge of the crystal blank 3 is the first distance. The width of the temperature-sensitive film 11 may be, for example, 1 / 5 or more, 1 / 3 or more, 1 / 2 or more, 2 / 3 or more, or 4 / 5 or more of the first distance, or may be 1 or less, 9 / 10 or less, 4 / 5 or less, or 2 / 3 or less. The above lower and upper limits may be combined with any one of them so long as no contradiction occurs. For example, the above may be true for most of the direction in which the temperature-sensitive film 11 extends (for example, 80% or more of the length).

[0072] When the width of the temperature-sensitive film 11 is smaller than the first distance, the temperature-sensitive film 11 may be closer to either the edge of the excitation electrode 7 or the edge of the crystal blank 3 in the width direction of the temperature-sensitive film 11 (here, the D1 direction), or may be disposed at an equal distance from both. An example of the former is a state in which the temperature-sensitive film 11 is closer to the crystal blank 3 than the excitation electrode 7, and more specifically, a state in which the edge of the temperature-sensitive film 11 and the edge of the crystal blank 3 roughly coincide with each other and the temperature-sensitive film 11 is separated from the excitation electrode 7. In this case, the area of ​​the temperature-sensitive film 11 can be secured while reducing the likelihood of a short circuit between the temperature-sensitive film 11 and the excitation electrode 7.

[0073] The temperature-sensitive film 11 may have a generally constant thickness over 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 having 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 indicated on the upper surface of the covering film that covers them.

[0074] 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 crystal 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.

[0075] (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 constituting the film body 11a (for example, the functional part (resistive film)). 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 crystal blank 3 (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, if a through hole is provided that penetrates the crystal blank 3 in the thickness direction, the external electrodes 11b may pass through the through hole.

[0076] As described 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 them. 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.

[0077] In the illustrated example, the pair of external electrodes 11b are located in different regions in the extension direction (the longitudinal direction from another perspective) of the thermosensitive membrane 11 (or the membrane body 11a; the same applies in this paragraph and the next paragraph unless there is any contradiction). 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 aspects other than those illustrated include an aspect 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 an aspect in which both of the pair of external electrodes 11b are located at one end of the thermosensitive membrane 11.

[0078] 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 description of the positions, the length of the external electrode 11b in the width direction of the temperature-sensitive membrane 11 may be more than or less than ½ of the width of the temperature-sensitive membrane 11. 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.

[0079] (3. Modifications of the position, shape and dimensions of the temperature-sensitive membrane) Fig. 3(a) is a plan view showing a quartz crystal element 1A according to a modified example, and Fig. 3(b) is a plan view showing a quartz crystal element 1B according to another modified example.

[0080] In the crystal element 1 according to the embodiment, the temperature-sensitive film 11 is shaped to extend along one edge of the crystal blank 3 (or the excitation electrode 7), which can have four edges. The temperature-sensitive film 11 may be shaped to extend along two or more edges. Figures 3(a) and 3(b) show examples of such shapes.

[0081] From another perspective, in the crystal element 1 according to the embodiment, the temperature-sensitive film 11 is shaped to have a portion located on the opposite side (+D1 side) of the extraction electrode 9 with respect to the excitation electrode 7. However, instead of or in addition to such a portion, the temperature-sensitive film 11 may have a portion located to the side (-D2 side and / or +D2 side) with respect to the direction from the excitation electrode 7 to the extraction electrode 9. Figures 3(a) and 3(b) show examples of such a shape.

[0082] 3(a), the temperature-sensitive film 11 extends along two edges. In other words, the shape of the temperature-sensitive film 11 is L-shaped. From another perspective, the temperature-sensitive film 11 has a portion located on either the -D2 side or the +D2 side (the +D2 side in the illustrated example) in addition to a portion located on the +D1 side.

[0083] 3(b), the temperature-sensitive film 11 extends along the three edges. In other words, the shape of the temperature-sensitive film 11 is U-shaped. From another perspective, the temperature-sensitive film 11 has a portion located on both the -D2 side and the +D2 side in addition to a portion located on the +D1 side.

[0084] In the following description, the portion of the temperature-sensitive film 11 that extends along one edge of the crystal blank 3 (or the excitation electrode 7) is referred to as the segment 11s. The description (e.g., description of the position, shape, and dimensions) of the temperature-sensitive film 11 (segment 11s extending in the D2 direction from another perspective) in the crystal element 1 may be applied to each segment 11s in the crystal elements 1A and 1B. In this case, the D1 direction and the D2 direction, etc. may be appropriately replaced with each other.

[0085] As is clear from the fact that the description of the segment 11s extending in the D2 direction may be applied to the segment 11s extending in the D1 direction, the segment 11s extending in the D1 direction may extend to a position on the -D1 side of the edge of the excitation electrode 7 on the extraction electrode 9 side (-D1 side) (Figure 3(b)), or may extend to the position of the above-mentioned edge (Figure 3(a)), or may not extend to the above-mentioned edge.

[0086] The two or more segments 11s may have the same configuration as each other, or may have different configurations. For example, the segment 11s extending in the D2 direction and the segment 11s 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 11s extending in the D2 direction and the segment 11s extending in the D1 direction may both be linear, or one may be linear and the other may be curved.

[0087] 3(a) and 3(b), the pair of external electrodes 11b are located on the segment 11s extending in the D2 direction, similar to the example in FIG. 1. Unlike the illustrated example, at least one of the pair of external electrodes 11b may be located on the segment 11s extending in the D1 direction. Also, for example, the pair of external electrodes 11b may be located across two or more segments 11s. For example, the two external electrodes 11b may be located at both ends of the entire thermosensitive film 11 in the extension direction of the thermosensitive film 11.

[0088] When one external electrode 11b is located at an end of the thermosensitive membrane 11 (or segment 11s; the same applies below in this paragraph), the external electrode 11b may be located in an end region when the length of the thermosensitive membrane 11 is divided into thirds, fifths, or sevenths. Conversely, when one external electrode 11b is located in the center of the thermosensitive membrane 11, the external electrode 11b may be located in the center region when the length of the thermosensitive membrane 11 is divided into thirds, fifths, or sevenths.

[0089] FIG. 4 is a table showing further various modifications regarding the position, shape and size of the temperature-sensitive film 11. In FIG.

[0090] As can be seen from the symbols shown in the lower left of the figure, each square shows a schematic representation of a crystal blank 3, an excitation electrode 7, an extraction electrode 9 and a temperature-sensitive film 11. The four columns correspond to modified examples having different numbers of segments 11s. The top square (the squares showing the numbers "1", "2", "3" and "4") shows the number of segments 11s in each column. The multiple rows (excluding the top square) correspond to modified examples having different positions of the segments 11s.

[0091] In the first row, an embodiment in which the temperature-sensitive film 11 has one segment 11s is shown. The position of the segment 11s may be on the opposite side (+D1 side) of the excitation electrode 7 from the extraction electrode 9 shown in FIG. 1, or may be on the lateral side (+D2 side or -D2 side) from the excitation electrode 7 toward the extraction electrode 9 (first and second rows), or on the extraction electrode 9 side (-D1 side) (third and fourth rows). In an embodiment in which the segment 11s is located on the extraction electrode 9 side, the temperature-sensitive film 11 may not overlap the extraction electrode 9 (third row), or may overlap it (fourth row). In an overlapping embodiment, as described above, an insulating film may be interposed between the functional part of the temperature-sensitive film 11 (resistance film in the case of a thermistor) and the extraction electrode 9.

[0092] In the second column, the thermosensitive film 11 has two segments 11s. The positions of the two segments 11s may be +D1 and -D2 (first row), -D1 and +D2 (second row), or -D1 and -D2 (third row) in addition to the +D1 and +D2 sides shown in FIG. 3(a). The -D2 and +D2 sides can be said to be the extraction electrode 9 side and the opposite side thereof that are extracted from the excitation electrode 7 that overlaps the surface (first surface 3a here) on which the thermosensitive film 11 overlaps in the arrangement direction (D2 direction) of a pair of extraction electrodes 9. As can be seen from the first column, the segment 11s located on the extraction electrode 9 side (-D1 side) may not overlap the extraction electrode 9 (in the illustrated example) in the mode (second row) where it is connected to the segment 11s on the +D2 side.

[0093] In the third column, an embodiment in which the temperature-sensitive film 11 has three segments 11s is shown. The positions of the three segments 11s may be the +D1 side, +D2 side and -D1 side (first row), the +D1 side, -D2 side and -D1 side (second row), or the -D2 side, -D1 side and -D2 side (third row) in addition to the -D2 side, +D1 side and -D2 side shown in Fig. 3(b). The embodiment in which the segment 11s located on the -D1 side is not connected to the segment 11s on the -D2 side (first row) may not overlap the extraction electrode 9 (as shown in the example), or may overlap.

[0094] The fourth column shows an embodiment in which the temperature-sensitive film 11 has four segments 11s. In this case, the temperature-sensitive film 11 may be partially interrupted (first row) or may be connected in a ring shape (second row). In the former embodiment, the temperature-sensitive film 11 may not overlap the extraction electrode 9 (as shown in the example), or may overlap it.

[0095] The shape of the temperature-sensitive film 11 can be various other than the shapes described above. For example, the temperature-sensitive film 11 may have a shape that does not allow the concept of the segments 11s. Such a shape may be, for example, a shape in which neither the crystal blank 3 nor the excitation electrode 7 has four edges (e.g., a circle), and the segments 11s are arc-shaped or circumferential.

[0096] Note that if four edges can be conceived of at least one of the crystal blank 3 and the excitation electrode 7, even if the temperature-sensitive film 11 is arc-shaped or circumferential, the boundaries between the segments 11s will be unclear, but it is possible to identify the presence of the segments 11s. Similarly, even if four edges cannot be conceived of either the crystal blank 3 or the excitation electrode 7, it is possible to conceive of the segments 11s if the temperature-sensitive film 11 is a combination of straight portions. The explanations given so far regarding the segments 11s can be applied.

[0097] A modified example of the length of the temperature-sensitive film 11 will be described using a concept different from that of the segment 11s. For example, the temperature-sensitive film 11 may be in an angular range around the geometric center of the excitation electrode 7 or the crystal blank 3 within a range of 90° or less, 90° to 180°, 180° to 270°, or 270° to 360°. The direction of the angular range in which the temperature-sensitive film 11 is located is arbitrary. For example, the center direction of the angular range in which the temperature-sensitive film 11 is located may be the +D1 direction, the -D1 direction, the +D2 direction, or the -D2 direction.

[0098] In addition, in the explanation of the main body of the quartz crystal element (parts other than the temperature-sensitive film 11), it was stated that the quartz crystal element 1 may have various configurations (for example, the quartz crystal blank 3 does not have to be plate-shaped). In quartz crystal elements other than those shown in the drawings, the position, shape, and dimensions of the temperature-sensitive film 11 may be set as appropriate. For example, in an embodiment in which the quartz crystal blank is a tuning fork type having a base and a pair of vibrating arms extending in parallel from the base, the temperature-sensitive film 11 may be located, for example, on the base or on the vibrating arms. In an embodiment in which an AT-cut type or tuning fork type has a mounting arm or frame extending from a plate-shaped portion or a base, the temperature-sensitive film 11 may be provided on the mounting arm or frame.

[0099] (4. Examples of using quartz crystal elements) Fig. 5 is an exploded perspective view of a quartz crystal device 101 as an example of use of the quartz crystal element 1. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5.

[0100] The crystal device 101 is, for example, an electronic component that has a generally rectangular parallelepiped shape. 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).

[0101] The crystal device 101 is configured as, for example, a crystal resonator. 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 contributing to electrical connection between the crystal element 1 and the mounting base (not shown).

[0102] 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 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.

[0103] 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 substrate portion 111a and the frame portion 111b may be made of any material, such as ceramic. The substrate portion 111a has a first substrate surface 111c that constitutes the bottom surface of the recess R1 and a second substrate surface 111d that constitutes the bottom surface of the crystal device 101.

[0104] Examples of conductors that the base 107 has include the following: Two first pads 113 and two second pads 115 that are electrically connected to the crystal element 1. Four external terminals 117 for mounting the crystal device 101 on a mounting base. Four wiring conductors 119 that connect the above four pads (113 and 115) to the four external terminals 117.

[0105] 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.

[0106] The first pad 113 and the second pad 115 are formed of a conductive 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) in the longitudinal direction of the substrate portion 111a. The two second pads 115 are lined up in the short direction of the substrate portion 111a at the other end side (+D1 side) in the longitudinal direction of the substrate portion 111a.

[0107] Since the external electrode 11b and the second pad 115 are connected by the bonding wire 121, they do not necessarily need to be located close to each other. As described above, the external electrode 11b does not need to overlap the film body 11a, and can be located at any position relative to the film body 11a. Furthermore, the planar shape of the film body 11a can be various shapes. As can be understood from the above, the position of the second pad 115 is arbitrary. For example, unlike the illustrated example, at least one second pad 115 may be located at the center side in the longitudinal direction of the first substrate surface 111c or adjacent to the first pad 113.

[0108] The external terminals 117 are formed of a conductor layer (e.g., metal) that overlaps the second substrate surface 111d. The positions, shapes, and dimensions of the external terminals 117 are arbitrary. For example, four external terminals 117 are located at the four corners of the second substrate surface 111d.

[0109] 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 part 111a, and the latter two external terminals 117 may be located on the other side (+D2 side) in the longitudinal direction of the substrate part 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.

[0110] 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.

[0111] 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 positions of the external electrode 11b and 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 upper surface of the crystal element 1 to the first substrate surface 111c.

[0112] Although not specifically shown, a support member for supporting 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.

[0113] The lid 109 is, for example, a flat plate-like member made of an insulator or a metal. The method of joining the lid 109 to the base 107 is also arbitrary. For example, the two may be joined by seam welding. In the illustrated example, metal layers 123 and 125 used for seam welding are illustrated. In an embodiment in which the lid 109 is made of a 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).

[0114] The quartz crystal element 1 may be used in various other ways in addition to the above-mentioned examples of use.

[0115] 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.

[0116] As can be understood from the above, the number of pads and the number of external terminals that the crystal device has are arbitrary, and the connection relationship between the multiple pads and the multiple external terminals is also arbitrary. For example, in an oscillator, the crystal element 1 (the extraction electrode 9 and the external electrode 11b) may be electrically connected to an IC instead of an external terminal.

[0117] 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 upper and lower surfaces. In this case, for example, the above-mentioned IC may be mounted in the recess on the lower surface. The package may also be configured with a substrate-like base (a base without a recess) and a cap-like lid that is placed on the base. For example, the piezoelectric device (package) may also have a thermostatic oven.

[0118] (5. 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 two excitation electrodes 7 overlap the surface of the crystal blank 3. The two extraction electrodes 9 are extracted from the two excitation electrodes 7. The temperature-sensitive film 11 has a portion (the entire temperature-sensitive film 11 in the illustrated example) that overlaps with an area of ​​the surface of the crystal blank 3 that is different from the area where the two excitation electrodes 7 overlap.

[0119] 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.

[0120] The crystal blank 3 may have a plate-shaped portion (the entire crystal blank 3 in the illustrated example). The plate-shaped portion has a first surface 3a and a second surface 3b facing opposite sides in the thickness direction. The two excitation electrodes 7 may have a first excitation electrode (excitation electrode 7 on the +D3 side) overlapping the first surface 3a, and a second excitation electrode (excitation electrode 7 on the -D3 side) overlapping the second surface 3b. The temperature-sensitive film 11 may have a portion of the first surface 3a that overlaps the area between the first excitation electrode and the outer edge of the first surface 3a (the entire temperature-sensitive film 11 in the illustrated example).

[0121] In a configuration in which two excitation electrodes 7 face each other across a plate-shaped portion, the crystal blank 3 is intended to vibrate the portion (vibration portion) 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, for example, it is possible to ensure the area of ​​the temperature-sensitive film 11 while reducing the effect of the mass of the temperature-sensitive film 11 on the vibration of the vibration portion.

[0122] The two extraction electrodes 9 may have two wiring portions 9a and two terminal portions 9b. The two wiring portions 9a may extend from the excitation electrode 7 to the first side (-D1 side). The two terminal portions 9b may be connected to the two excitation electrodes 7 via the two wiring portions 9a and may be located at the end of the first side (-D1 side) of at least one of the first surface 3a and the second surface 3b. The temperature-sensitive film 11 may have a portion (the entire temperature-sensitive film 11 in the illustrated example) that is located closer to the two excitation electrodes 7 than the two terminal portions 9b.

[0123] In this case, for example, the temperature-sensitive film 11 can be said to be located in an area relatively close to the vibrating part excited by the two excitation electrodes 7. Therefore, it is easy to make the measured temperature follow the temperature of the vibrating part. The crystal element 1 is surrounded by a vacuum state or a gas with a lower thermal conductivity than a solid. Meanwhile, heat from outside the package 103 is transferred to the crystal blank 3 via the wiring conductor 119, the first pad 113, the bonding material 105, and the extraction electrode 9. Therefore, the temperature of the crystal blank 3 is likely to change from the extraction electrode 9 side. As a result, for example, in a mode in which the temperature-sensitive film 11 only has a portion that overlaps with the two extraction electrodes 9 and the area between them (this mode may also be included in the technology according to the present disclosure), the measured temperature may change before the temperature of the vibrating part, or the measured temperature may change more than the temperature of the vibrating part. By having a portion of the temperature-sensitive film 11 located closer to the excitation electrode 7 than the extraction electrode 9, such a phenomenon can be reduced.

[0124] In the above-mentioned embodiment in which the temperature-sensitive film 11 has only the two extraction electrodes 9 and the area between them, the effect of the mass of the temperature-sensitive film 11 on the vibration of the vibrating part is reduced. As can be understood from the explanation in the previous paragraph, the positions of the various segments 11s shown in Fig. 4 affect, for example, the followability of the measured temperature to the temperature of the vibrating part. From this perspective, the number and positions of the segments 11s may be designed taking into account the configuration of the package 103 and the environment in which the crystal device 101 is used.

[0125] The crystal device 101 according to this embodiment includes the above-described piezoelectric vibration element (crystal element 1) and a package 103 that holds the crystal element 1. As a result, the crystal element 1 having the temperature-sensitive film 11 provides various effects.

[0126] 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. The temperature sensitive film 11 may have a portion located on the surface of the quartz crystal blank 3 opposite the first substrate surface 111c (the surface on the +D3 side).

[0127] 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 an embodiment 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 an unintended change in stress occurs only in the region of the excitation electrode 7 (stress distribution becomes uneven). In addition, for example, it is expected that the mass change of the temperature-sensitive film 11 can also be used for frequency adjustment, and the adjustable range can be expanded. In addition, for example, in an embodiment in which the external electrode 11b of the temperature-sensitive film 11 is located on the first surface 3a, a bonding wire 121 can be used for electrical connection between the temperature-sensitive film 11 and the package 103. Compared to an embodiment in which a bonding material 127 (FIG. 9) described later is used, the influence of the electrical connection of the temperature-sensitive film 11 on the vibration of the crystal element 1 is reduced.

[0128] <Second embodiment> 7 and 8 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.

[0129] 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 to 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. For example, the modified examples shown in Figures 3(a), 3(b) and 4 may be applied to the quartz crystal element 201.

[0130] 9 is a cross-sectional view showing a quartz crystal device 101A as an example of use of the quartz crystal element 201 according to the second embodiment. This figure corresponds to FIG. 6 of the first embodiment.

[0131] In the crystal device 101A, the temperature-sensitive film 11 (more specifically, the external electrode 11b shown in FIG. 8) located on the lower surface of the crystal element 201 and the second pad 115 of the package 103 are bonded with a conductive bonding material 127. This electrically connects the temperature-sensitive film 11 and the external terminal 117.

[0132] At least a portion of the second pad 115 faces at least a portion of the external electrode 11b. As described in the first embodiment, the external electrode 11b may be disposed at any position. Therefore, the positions of the second pad 115 and the bonding material 127 are also arbitrary. For example, the second pad 115 may be located at one end in the longitudinal direction of the first substrate surface 111c as in the illustrated example, or may be located on the other end side in the longitudinal direction from such a position.

[0133] 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. 6) and the bonding material 127, the configurations of the second pad 115 and the external electrode 11b may be different between the first and second embodiments.

[0134] 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.

[0135] As described above, in this embodiment, the crystal element 201 also has a temperature-sensitive film 11, and the temperature-sensitive film 11 has a portion (in the illustrated example, the entire temperature-sensitive film 11) that overlaps with an area of ​​the surface of the crystal blank 3 that is different from the area where the two excitation electrodes 7 overlap. Therefore, the same effects as in the first embodiment are achieved.

[0136] The 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 crystal element 1. The temperature sensitive film 11 may have a portion located on the surface of the first substrate surface 111c of the crystal blank 3 (second surface 3b).

[0137] In this case, for example, in a mode in which the excitation electrode 7 on the first surface 3a is cut for frequency adjustment after the crystal element 201 is mounted and before sealing with the lid 109, the likelihood of the temperature-sensitive film 11 being cut together is reduced. As a result, for example, in a mode in which the functional portion of the temperature-sensitive film 11 (resistive film in the case of a thermistor) is exposed, the likelihood of the characteristic change of the functional portion is reduced. From another perspective, the need for providing a protective film to cover the functional portion is reduced.

[0138] <Third embodiment> 10 is a perspective view showing a crystal element 301 according to the third embodiment. This figure corresponds to FIG. 1 of the first embodiment.

[0139] 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 surface (-D2 side surface, +D2 side surface, -D1 side surface, and / or +D1 side surface) of the quartz crystal blank 3 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.

[0140] Unlike the illustrated example, for example, the temperature sensing portion 11 may not be connected between the portion on the first surface 3a and the portion on the second surface 3b, and each may be provided with two external electrodes 11b. Also, for example, the functional portion of the film body 11a (resistive film in a thermistor) may not be connected between the portion on the first surface 3a and the portion on the second surface 3b, and the conductor may be connected between the portion on the first surface 3a and the portion 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 crystal blank 3 in the thickness direction, the portion on the first surface 3a and the portion on the second surface 3b may be connected via the through hole (e.g., a slit).

[0141] The explanations of the first and second embodiments may be applied to this embodiment. For example, the modified examples shown in Figs. 3(a), 3(b) and 4 may be applied to this embodiment. That is, the shapes of the parts of the temperature-sensitive film 11 located on the first surface 3a and the second surface 3b may be various shapes. The shape of the part located on the first surface 3a and the shape of the part located on the second surface 3b may be the same or different. From another point of view, the two may overlap in large portions (for example, 80% or more of the area of ​​each part) or may not overlap in large portions.

[0142] The position, shape, and dimensions of the portion of the temperature-sensitive film 11 that connects the portion of the first surface 3a and the portion of the second surface 3b are also arbitrary. For example, in the case where overlapping segments 11s are provided, the connection may be made at any one, two, or three of the two short sides and one long side (the three sides along the outer edge of the crystal blank 3) of the segments 11s. Also, for example, the connection may be made over the entire long side of the segments 11s, or only a part of the long side.

[0143] As described above, in this embodiment, the crystal element 301 also has a temperature-sensitive film 11, and the temperature-sensitive film 11 has a portion (in the illustrated example, the entire temperature-sensitive film 11) that overlaps with an area of ​​the surface of the crystal blank 3 that is different from the area where the two excitation electrodes 7 overlap. Therefore, the same effects as in the first embodiment are achieved.

[0144] <Fourth embodiment> Fig. 11 is a perspective view showing a quartz crystal element 401 according to the fourth embodiment. This figure corresponds to Fig. 1 of the first embodiment. Fig. 12(a) is a cross-sectional view taken along line XII-XII in Fig. 11.

[0145] The crystal element 401 differs from the crystal element 1 of the first embodiment in the configuration of the crystal blank. Specifically, the crystal blank 403 of the crystal element 401 has a buffer section 13 located between the two excitation electrodes 7 and the temperature-sensitive film 11 in a planar perspective. From another perspective, the crystal blank 403 has a first region 403c and a second region 403d separated by the buffer section 13 in a planar perspective (reference numerals shown in FIG. 12(a)). Two excitation electrodes 7 are located in the first region 403c. The temperature-sensitive film 11 is located in the second region 403d.

[0146] The buffer section 13, for example, serves to reduce the effect that the mass of the temperature-sensitive film 11 has on vibrations in the first region 403c. In the example shown, the buffer section 13 is configured as a slit (a type of through hole) that penetrates the crystal blank 403 in the thickness direction and extends along the main surfaces (first surface 403a and second surface 403b) of the crystal blank 403.

[0147] In the illustrated example, the temperature-sensitive film 11 is located on the first surface 403a and has three segments 11s. However, the position, shape and dimensions of the temperature-sensitive film 11 combined with the buffer section 13 are arbitrary. For example, the temperature-sensitive film 11 may be any of the aspects of the first to third embodiments, and may have one, two or four segments 11s.

[0148] Just as the temperature-sensitive film 11 is considered to be composed of one or more segments 11s, when the buffer section 13 is considered to be composed of a plurality of segments (reference numbers omitted), the correspondence between the numbers of both is arbitrary.

[0149] For example, assume that the temperature-sensitive film 11 has the segment 11s only on one side of the crystal element 401 (and / or the excitation electrode 7) in planar perspective (considering both the first surface 403a and the second surface 403b). In this case, the buffer section 13 may have only one segment along the one side, or may have segments (but not connected in a ring shape) along two, three, or four sides including the one side. Also assume that the temperature-sensitive film 11 has only the segment 11s along two sides in planar perspective. In this case, the buffer section 13 may have only segments along the two sides, may have only segments along one of the two sides, or may have segments along three or four sides including the two sides.

[0150] In a higher-level concept, the buffer section 13 may have segments along all the sides (one or more and four or less) along which the segment 11s is located in planar perspective (illustrated example). The buffer section 13 may also have segments along all the sides (one or more and three or less) along which the segment 11s is located and other sides (one or more). The other sides are, for example, sides connected to the side along which the segment 11s is located (a side that is separate is also possible). The buffer section 13 may also have segments only along a part (one or more and three or less) of all the sides (two or more and four or less) along which the segment 11s is located. The buffer section 13 may also have segments only along a part (one or two) of all the sides (two or three) along which the segment 11s is located and other sides (one or two).

[0151] The length of the buffer section 13 along the edge of the excitation electrode 7 and / or the temperature-sensitive film 11 may be set appropriately. For example, the length of the buffer section 13 may be shorter than the length of the temperature-sensitive film 11 (as in the illustrated example) or longer. The length of the buffer section 13 may be, for example, 1 / 2 or more, 2 / 3 or more, 4 / 5 or more, or 1 time or more the length of the temperature-sensitive film 11. The above is a comparison between the total length of the buffer section 13 and the total length of the temperature-sensitive film 11, but it may also be true when comparing parallel segments.

[0152] In the illustrated example, the edge of the excitation electrode 7 and the edge of the temperature-sensitive film 11 are parallel to each other. The buffer section 13 extends along (more specifically, parallel to) the above-mentioned two edges with a generally constant width. More specifically, the buffer section 13 (each of its segments) extends linearly.

[0153] As described above, the shape of the excitation electrode 7 is not limited to a rectangle. For example, the edge of the excitation electrode 7 and the edge of the temperature-sensitive film 11 (or the entire temperature-sensitive film 11) may extend in a curved shape parallel to each other. In such a case, the buffer section 13 may extend along (parallel to) the edge of the excitation electrode 7 and the edge of the temperature-sensitive film 11, for example, with a substantially constant width. From another perspective, the buffer section 13 may extend in a curved shape.

[0154] In the case where the edge of the excitation electrode 7 and the edge of the temperature-sensitive film 11 (or the entire temperature-sensitive film 11) are not parallel to each other, the buffer section 13 may extend along (parallel to) one of the above-mentioned edges with, for example, a substantially constant width. Alternatively, for example, the buffer section 13 may extend while changing its width so that the distance between the two edges is substantially constant.

[0155] The above is an example of the planar shape of the buffer section 13, and the buffer section 13 may have other shapes. For example, the buffer section 13 does not have to be parallel to both the edge of the excitation electrode 7 and the edge of the temperature-sensitive film 11. Even if the edge of the excitation electrode 7 and the edge of the temperature-sensitive film 11 are parallel, the width of the buffer section 13 may vary. Also, for example, the buffer section 13 may be shorter than the example shown in the figure (or may have a shape in which the long side and short side directions cannot be distinguished), and multiple buffer sections 13 may be arranged along the edge of the excitation electrode 7.

[0156] In a cross section perpendicular to the direction in which the buffer section 13 extends in a plan view (e.g., the cross section shown in FIG. 12(a)), the shape and dimensions of the buffer section 13 are arbitrary. For example, the buffer section 13 may penetrate the crystal blank 403 with a constant width, or may have a narrower width toward the +D3 side, the -D3 side, or toward the middle position in the D3 direction. The cross-sectional shape and / or dimensions of the buffer section 13 may also differ depending on the direction in which the buffer section 13 extends. In the illustrated example, the width of the buffer section 13 (e.g., maximum width or average width) is relatively small, and is smaller than, for example, the width of the temperature-sensitive film 11 (e.g., minimum width or average width), the thickness of the crystal blank 403 (e.g., minimum thickness or average thickness), and the width of the wiring section 9a of the extraction electrode 9 (e.g., minimum width or average width).

[0157] Figures 12(b) and 12(c) are cross-sectional views showing modified examples of the buffer section 13. These figures correspond to Figure 12(a).

[0158] In the modified example shown in FIG. 12(b), crystal blank 403A has a concave portion (more specifically, for example, a groove) as buffer portion 13A. In the modified example shown in FIG. 12(c), crystal blank 403B has a convex portion (more specifically, for example, a ridge) as buffer portion 13B. The explanation of buffer portion 13 may be applied to buffer portions 13A and 13B as long as no contradiction arises. For example, the planar shape of buffer portions 13A and 13B may be the same as the planar shape of buffer portion 13. Furthermore, the cross-sectional shapes and / or dimensions of buffer portions 13A and 13B may differ depending on the direction in which these buffer portions extend.

[0159] In a cross section (e.g., the cross section shown in FIG. 12(c)) perpendicular to the direction in which the buffer section 13A (recess) extends in a plan view, the shape and dimensions of the buffer section 13A are arbitrary. For example, the buffer section 13A may be dug into the crystal blank 403A by 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 section 13A may be a shape with a bottom surface (as shown in the illustrated example), or a shape without a bottom surface (e.g., a V-groove shape). In the illustrated example, the width of the buffer section 13A is relatively small, similar to the buffer section 13. The depth (e.g., the maximum depth) of the buffer section 13A may be less than ½, about ½ (as shown in the illustrated example), or more than ½ of the thickness of the crystal blank 403A (thickness at the position of the buffer section 13).

[0160] In a cross section (e.g., the cross section shown in FIG. 12(b)) perpendicular to the direction in which the buffer section 13B (convex section) extends in a plan view, the shape and dimensions of the buffer section 13B are arbitrary. For example, the buffer section 13B may protrude with a constant width, or may have a width that narrows toward the tip. The cross-sectional shape of the buffer section 13B may have a top surface (as in the illustrated example), or may have a shape without a top surface (e.g., a triangular shape). In the illustrated example, the width of the buffer section 13B is relatively small, similar to the buffer section 13. The height (e.g., the maximum height) of the buffer section 13B 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 403A (the thickness at the position of the buffer section 13, or the minimum or maximum thickness).

[0161] The relationship between the surface on which the temperature-sensitive film 11 is located and the surface on which the buffer section 13A or 13B is located is arbitrary. For example, as in the illustrated example, in an embodiment in which the temperature-sensitive film 11 is located on only one of the first surface 403a and the second surface 403b, the buffer section 13A or 13B may be located on the same surface as the surface on which the temperature-sensitive film 11 is located (the first surface 403a in the illustrated example), or on the opposite surface (the second surface 403b in the illustrated example), or on both surfaces. Also, for example, in an embodiment in which the temperature-sensitive film 11 is located on both the first surface 403a and the second surface 403b, the buffer section 13A or 13B may be located on only one surface, or on both surfaces.

[0162] Although not particularly shown, the buffer sections 13, 13A, and 13B 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, the buffer section 13A may be provided on one of the first surface 403a and the second surface 403b, and the buffer section 13B may be provided on the other surface.

[0163] As described above, in this embodiment, the crystal element 401 also has a temperature-sensitive film 11, and the temperature-sensitive film 11 has a portion (in the illustrated example, the entire temperature-sensitive film 11) that overlaps with an area of ​​the surface of the crystal blank 403 (or 403A or 403B) different from the area where the two excitation electrodes 7 overlap. Therefore, the same effects as in the first embodiment are achieved.

[0164] The piezoelectric body (crystal blank 403, 403A or 403B) may have a buffer section 13 (13A or 13B) located between the two excitation electrodes 7 and the temperature-sensitive film 11 in a planar perspective view of the first surface 403a. The buffer section 13 may include at least one of a recess on the first surface 403a, a recess on the second surface 403b, a protrusion on the first surface 403a, a protrusion on the second surface 403b, and a through hole.

[0165] In this case, for example, as described above, the effect of the mass of the temperature-sensitive film 11 on the vibration of the vibration part sandwiched between the two excitation electrodes 7 of the crystal blank 403 is reduced. As a result, for example, the design of the crystal element 401 is simplified. Also, the likelihood that an error in the characteristics of the crystal element 401 will occur due to an error in the mass of the temperature-sensitive film 11 is reduced. From another perspective, the degree of freedom of the position of the temperature-sensitive film 11 is improved.

[0166] <Fifth embodiment> Fig. 13 is a perspective view showing a crystal element 501 according to the fifth embodiment. This figure corresponds to Fig. 1 of the first embodiment. Fig. 14 is a cross-sectional view taken along line XIV-XIV in Fig. 13.

[0167] The crystal element 501 differs from the crystal element 1 of the first embodiment in the configuration of the crystal blank. Specifically, in the crystal blank 503 of the crystal element 501, the thickness of the first region 503c where the excitation electrode 7 is located is thinner than the thickness of the second region 503d where the temperature-sensitive film 11 is located. By making the second region 503d thicker, for example, the proportion of the mass per unit area of ​​the temperature-sensitive film 11 to the mass per unit area of ​​the crystal blank 503 is reduced. This reduces, for example, the effect of the mass of the temperature-sensitive film 11 on the vibration in the first region 503c.

[0168] In the illustrated example, the temperature-sensitive film 11 is located on the first surface 503a and has three segments 11s. However, the position, shape and dimensions of the temperature-sensitive film 11 are arbitrary. For example, the temperature-sensitive film 11 may be any of the aspects of the first to third embodiments, and may have one, two or four segments 11s.

[0169] As described above, the first region 503c is a portion where the two excitation electrodes 7 overlap (a part of the first region 503c may be regarded as the first region 503c). However, for convenience, in the description of the embodiment, in addition to the overlapping region where the excitation electrodes 7 overlap, the whole including other regions having the same thickness as the thickness of the overlapping region may be referred to as the first region 503c. Also, as described above, the second region 503d is a portion where the thermosensitive film 11 overlaps (a part of the second region 503d may be regarded as the second region 503d). However, for convenience, in the description of the embodiment, in addition to the overlapping region where the thermosensitive film 11 overlaps, the whole including other regions having the same thickness as the thickness of the overlapping region may be referred to as the second region 503d.

[0170] The thickness of the first region 503c is, for example, a constant thickness over the entire width of the two excitation electrodes 7. Similarly, the thickness of the second region 503d is, for example, a constant thickness over the entire width of the thermosensitive film 11. In the description of this embodiment, expressions based on such a mode may be used. However, a part or all of the outer periphery of the excitation electrode 7 may extend into the relatively thick region. Similarly, a part of the thermosensitive film 11 may extend into the relatively thin region. As can be understood from the description of this paragraph, when the thickness of the second region where the thermosensitive film 11 is located is thicker than the thickness of the first region where the excitation electrode 7 is located, such a thickness relationship does not have to be established over the entire width of the thermosensitive film 11 and the entire width of the excitation electrode 7. The area where such a relationship holds may be, for example, ⅔ or more or the entire area of ​​one excitation electrode 7, and ½ or more, ⅔ or more or the entire area of ​​the temperature-sensitive film 11 (upper or lower surface).

[0171] Just as the thermosensitive film 11 is considered to be composed of one or more segments 11s, the second region 503d can be considered to be composed of a plurality of segments (reference numerals omitted). In this case, the segments (sides on the -D1 side in the illustrated example) on which the thermosensitive film 11 can be placed and on which the thermosensitive film 11 is not located may be relatively thick regions (second region 503d) (illustrated example) or relatively thin regions (first region 503c). In addition, when there are two or more segments (sides) on which the thermosensitive film 11 can be placed and on which the thermosensitive film 11 is not located, the number of relatively thick (or thin) regions is arbitrary, and may be all or a part of them.

[0172] In the crystal blank 503, the segment in which the temperature-sensitive film 11 is located is basically a relatively thick region (second region 503d). The entire portion of the temperature-sensitive film 11 located in the segment is located in the relatively thick region. However, unlike the illustrated example, some of the segments in which the temperature-sensitive film 11 is located, or some of the segments in which the temperature-sensitive film 11 is located, may have relatively thin portions.

[0173] In the illustrated example, the edge of the excitation electrode 7 and the edge of the crystal blank 503 are parallel to each other. The relatively thick region (second region 503d) extends along (more specifically, parallel to) the above two edges with a generally constant width. More specifically, the outer edge of the relatively thick region coincides with the edge of the crystal blank 503. The relatively thick region (each of its segments) extends linearly. The temperature-sensitive film 11 extends linearly with a generally constant width, similar to the relatively thick region. However, the outer edge of the relatively thick region does not have to coincide with the edge of the crystal blank 503, and the planar shape of the temperature-sensitive film 11 (each of the segments 11s) does not have to be similar to the planar shape of the relatively thick region (the portion corresponding to each of the segments 11s).

[0174] As described above, the planar shape of the excitation electrode 7 and the planar shape of the crystal blank 503 are not limited to a rectangle. For example, the edge of the excitation electrode 7 and the edge of the crystal blank 503 may extend in a curved shape parallel to each other. In such a case, the relatively thick region (second region 503d) may extend along (parallel to) the edge of the excitation electrode 7, for example, with a generally constant width. From another perspective, the relatively thick region may extend in a curved shape. In this case, the outer edge of the relatively thick region may or may not match the edge of the crystal blank 503, and the planar shape of the temperature-sensitive film 11 (each segment 11s) may or may not be similar to the planar shape of the relatively thick region (the portion corresponding to each segment 11s).

[0175] When the edge of the excitation electrode 7 and the edge of the crystal blank 503 are not parallel to each other, the relatively thick region (second region 503d) may extend while changing its width, for example, so that the distance between the inner edge and the edge of the excitation electrode 7 is generally constant and the outer edge and the edge of the crystal blank 503 coincide (or the distance is generally constant). In this case, the planar shape of the temperature-sensitive film 11 (each segment 11s) may or may not be similar to the planar shape of the relatively thick region (the portion corresponding to each segment 11s). For example, each segment 11s may extend linearly with a constant width.

[0176] Note that the above is one example of the planar shape of the relatively thick region (second region 503d), and the planar shape may be other shapes. For example, the relatively thick region does not have to be parallel to both the edge of excitation electrode 7 and the edge of crystal blank 503. Even if the edge of excitation electrode 7 and the edge of crystal blank 503 are parallel, the width of the relatively thick region may vary.

[0177] Between the relatively thin region (first region 503c) and the relatively thick region (second region 503d), there may or may not be a portion where the thickness gradually changes from the former thickness to the latter thickness. From another point of view, there may or may not be an inclined surface between the two. The angle of the inclined surface may be any size, and may be determined by the angle of a crystal plane that appears due to the anisotropy of quartz with respect to etching. The inclined surface may have a recess that spans from the relatively thin region to the relatively thick region. Such a recess may contribute to, for example, facilitating the formation of a conductor layer that spans both regions.

[0178] In the illustrated example, the relatively thick region (second region 503d) is thicker on the side facing the first surface 503a than the relatively thin region (first region 503c). The first surface 503a is the surface that faces the opposite side to the substrate portion 111a of the package 103 after mounting. In the illustrated example, the first surface 503a is the surface on which the temperature-sensitive film 11 is located in a mode in which the temperature-sensitive film 11 is located on only one of the first surface 503a and the second surface 503b.

[0179] However, the combination of the direction of thickening (+D3 side and / or -D3 side) and the arrangement of the thermosensitive film 11 is arbitrary. For example, unlike the illustrated example, the second region 503d may be thickened on the side facing the second surface 503b (the side of the substrate part 111a after mounting), or may be thickened on both the side facing the first surface 503a and the side facing the second surface 503b. Also, for example, in a mode in which the second region 503d is thickened only on one side of the side facing the first surface 503a and the side facing the second surface 503b, the thermosensitive film 11 may be located only on the surface that is not thickened (the second surface 503b in the illustrated example) or may be located on both surfaces, unlike the illustrated example.

[0180] In the illustrated example, in a configuration in which the temperature-sensitive film 11 is located only on the surface on the side where the second region 503d is thick (first surface 503a in the illustrated example), the mass of the crystal blank 503 between the first region 503c and the temperature-sensitive film 11 is 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. Unlike the illustrated example, in a configuration in which the temperature-sensitive film 11 is located only on the surface on the side where the second region 503d is not thick (second surface 503b in the illustrated example), for example, the mass of the crystal blank 503 between the first region 503c and the temperature-sensitive film 11 is small, so 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 in which the temperature-sensitive film 11 is located on both sides, for example, the above effects are harmonious.

[0181] In the embodiment in which the second region portion 503d is thickened on both sides (the +D3 side and the -D3 side), the planar shape of the portion thickened on the +D3 side and the planar shape of the portion thickened on the -D3 side are, for example, roughly the same. However, they may be different. In any case, the above-mentioned explanation of the planar shape may be applied to each of the above two portions and their combination. In addition, the amount of thickening on the +D3 side and the amount of thickening on the -D3 side may be the same or different from each other. In addition, the thickness of the second region portion 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 the embodiment in which the second region portion 503d is thickened on one or both of the +D3 side and the -D3 side.

[0182] The area of ​​the relatively thin region (first region 503c) is, for example, equal to or greater than the area of ​​the excitation electrode 7, and the difference or ratio between the two is arbitrary. The distance between the edge of the former region and the edge of the excitation electrode 7 is also arbitrary. The width of the relatively thick region (second region 503d) is, for example, equal to or greater than the width of the temperature-sensitive membrane 11, and the difference or ratio between the two is arbitrary. For example, the center line of the segment 11s may be located on the inner side of the center line of the relatively thick region, may be coincident with the center line, or may be located on the outer side.

[0183] 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 one of them so as not to contradict each other. Also, 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 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 one of them so as not to contradict each other.

[0184] As described above, in this embodiment, the crystal element 501 also has a temperature-sensitive film 11, and the temperature-sensitive film 11 has a portion (in the illustrated example, the entire temperature-sensitive film 11) that overlaps with an area of ​​the surface of the crystal blank 503 that is different from the area where the two excitation electrodes 7 overlap. Therefore, the same effects as in the first embodiment are achieved.

[0185] The piezoelectric body (crystal blank 503) may have a first region 503c and a second region 503d which are different parts when the crystal blank 503 is viewed in the thickness direction (direction D3). At least a part of the two excitation electrodes 7 may be located in the first region 503c. At least a part of the temperature-sensitive film 11 may be located in the second region 503d. The thickness of the second region 503d may be greater than the thickness of the first region 503c.

[0186] 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. Also, the likelihood that an error in the characteristics of the crystal element 501 due to an error in the mass of the temperature-sensitive film 11 occurs is reduced. From another perspective, the degree of freedom in designing the temperature-sensitive film 11 is improved.

[0187] The configuration of this embodiment, in which the second region 503d is thicker than the first region 503c, may be applied to crystal blanks having shapes other than a plate shape. The configuration of this embodiment may be combined with various planar shapes as long as the crystal blank has a thickness. For example, in a tuning fork-shaped crystal blank, the second region (e.g., the base) may be thicker than the first region (the vibrating arm extending from the base).

[0188] In the above embodiments and modifications, the crystal elements 1, 1A, 1B, 201, 301, 401, and 501 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, 403A, 403B, 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.

[0189] The technology according to the present disclosure is not limited to the above-described embodiment and modifications, and may be implemented in various forms.

[0190] For example, the above-described embodiments and modifications may be appropriately combined. More specifically, for example, the configuration having the buffer portion of the fourth embodiment and the configuration in which the second region is thicker than the first region of the fifth embodiment may be combined.

[0191] The piezoelectric body is not limited to quartz. For example, the piezoelectric body may be another single crystal or may be made of polycrystal (e.g., ceramic). Note that quartz to which an appropriate dopant is added may be considered as a type of quartz.

[0192] The piezoelectric vibration element is not limited to one intended to generate an oscillation signal, and may be, for example, a piezoelectric gyro sensor.

[0193] 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 lead electrodes. Also, for example, the piezoelectric vibration element may have a conductive bonding material bonded to one lead electrode, and a bonding wire bonded to one lead electrode. Also, an insulating bonding material (which can be conductive) bonded to a region different from the region of the lead electrode may be used as a bonding material for supporting one or both ends of the piezoelectric vibration element. [Explanation of symbols]

[0194] 1...quartz crystal element (piezoelectric vibration element), 3...quartz crystal blank (piezoelectric body), 7...excitation electrode, 9...extraction electrode, 11...temperature-sensitive film, 101...quartz crystal device (piezoelectric device).

Claims

1. A piezoelectric body; Two excitation electrodes overlapping a surface of the piezoelectric body; Two extraction electrodes extending from the two excitation electrodes; a temperature-sensitive film having a portion overlapping a region of the surface of the piezoelectric body that is different from a region where the two excitation electrodes overlap; It has The piezoelectric body has a plate-shaped portion, The plate-shaped portion has a first surface and a second surface facing opposite sides in a thickness direction, the two excitation electrodes include a first excitation electrode overlapping the first surface and a second excitation electrode overlapping the second surface; the temperature-sensitive film has a portion of the first surface overlapping a region between the first excitation electrode and an outer edge of the first surface, the piezoelectric body has a buffer portion located between the two excitation electrodes and the temperature-sensitive film in a plan view of the first surface, 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.

2. The two extraction electrodes are Two wiring portions extending from the two excitation electrodes to a first side; two terminal portions connected to the two excitation electrodes via the two wiring portions and located at an end portion of the first side of at least one of the first surface and the second surface; The temperature-sensitive film has a portion located closer to the two excitation electrodes than the two terminal portions. The piezoelectric vibration element according to claim 1 .

3. The piezoelectric body is a first region in which at least a portion of the two excitation electrodes is located; a second region that is different from the first region when the piezoelectric body is viewed in a thickness direction, and in which at least a part of the temperature-sensitive film is located; The thickness of the second region is greater than the thickness of the first region. The piezoelectric vibration element according to claim 1 .

4. The piezoelectric vibration element according to any one of claims 1 to 3, A package that holds the piezoelectric vibration element; A piezoelectric device having a

5. 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 temperature-sensitive film has a portion located on a surface of the piezoelectric body opposite to the predetermined surface. The piezoelectric device according to claim 4 .

6. 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 temperature-sensitive film has a portion located on a surface of the piezoelectric body on the side of the predetermined surface. The piezoelectric device according to claim 4 .

Images