JP6779797B2 - Crystal device - Google Patents

Description

The present invention relates to a crystal device such as a crystal oscillator.

A conventional crystal device includes a package, an electrode pad provided on the package, a conductive adhesive provided on the electrode pad, a crystal element connected to the electrode pad via the conductive adhesive, and a package. It is provided with a lid that airtightly seals the crystal element by being joined to. The conductive adhesive on the electrode pad has a circular shape in a plan view (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2016-139901 Japanese Unexamined Patent Publication No. 2016-127375

In order to increase the connection strength between the crystal element and the conductive adhesive, it is necessary to increase the contact area between the crystal element and the conductive adhesive. In the conventional crystal device, in order to increase the contact area between the crystal element and the conductive adhesive, the diameter of the conductive adhesive applied in a circular shape to the electrode pad is increased. However, if the diameter of the conductive adhesive is increased, the conductive adhesive approaches the excitation electrode and the vibration of the crystal element is hindered, so that there is a problem that the equivalent series resistance value of the crystal element increases. It was. This problem is becoming more serious as the contact area is decreasing with the recent miniaturization of crystal devices.

Therefore, an object of the present invention is to provide a crystal device capable of increasing the contact area between the crystal element and the conductive adhesive without increasing the equivalent series resistance value of the crystal element.

The crystal device according to the present invention is
Package and
With the electrode pads provided on this package,
With the conductive adhesive provided on this electrode pad,
A crystal element connected to the electrode pad via this conductive adhesive and
It is provided with a lid that airtightly seals the crystal element by being joined to the package.
The crystal element is a rectangular plate-shaped crystal piece composed of a long side and a short side in a plan view , an excitation electrode provided on both sides of the crystal piece, and the short side of one of the crystal pieces from the excitation electrode. Has a lead-out electrode that is pulled out to
The electrode pad fixes the crystal element in a cantilever shape by electrically and mechanically connecting to the extraction electrode via a conductive adhesive.
Said conductive adhesive, Ri substantially elliptical shape der consisting perpendicular short axis to the long axis and the one short side which overlaps a short side of the one in a plan view, the drawer on the short side of the one In contact with the entire linear part of the electrode,
It is characterized by that.

According to the present invention, the conductive adhesive on the electrode pad has a substantially elliptical shape consisting of a long axis parallel to one side of the crystal piece provided with the extraction electrode and a short axis perpendicular to the side. The contact area between the crystal element and the conductive adhesive can be increased in the long axis direction without bringing the conductive adhesive close to the excitation electrode. Therefore, it is possible to provide a crystal device capable of increasing the contact area between the crystal element and the conductive adhesive without increasing the equivalent series resistance value of the crystal element.

It is a top view which shows the crystal device of Embodiment 1. FIG. It is an exploded perspective view which shows the crystal device of Embodiment 1. FIG. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 [A] is a partial plan view showing the crystal device of the first embodiment, and FIG. 4 [B] is a partial plan view showing the crystal device of Comparative Example 1. It is a top view which shows the modification of the conductive adhesive in the crystal device of Embodiment 1, FIG. 5 [A] is modification 1, FIG. 5 [B] is modification 2, and FIG. 5 [C] is modification 3. Is. It is a top view which shows the coating method of the conductive adhesive in the crystal device of Embodiment 1, FIG. 6 [A] is a 1st example, FIG. 6 [B] is a 2nd example, and FIG. 6 [C] is a 3rd example. Is. It is a top view which shows the crystal device of Embodiment 2. It is an exploded perspective view which shows the crystal device of Embodiment 2. FIG. 7 is a sectional view taken along line IX-IX in FIG.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the accompanying drawings. In the present specification and drawings, the same reference numerals are used for substantially the same components. The shapes drawn in the drawings are drawn for those skilled in the art to be easily understood, and therefore do not necessarily match the actual dimensions and ratios.

FIG. 1 is a plan view showing the crystal device of the first embodiment. FIG. 2 is an exploded perspective view showing the crystal device of the first embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 [A] is a partial plan view showing the crystal device of the first embodiment. Hereinafter, description will be given based on these drawings. In addition, in FIG. 1, the lid body is removed, and in FIG. 4 [A], a part of FIG. 1 is enlarged and shown.

The crystal device 10 of the first embodiment is conductively bonded to the package 20, the electrode pads 21 and 22 provided on the package 20, and the conductive adhesives 41 and 42 provided on the electrode pads 21 and 22. It includes a crystal element 30 connected to the electrode pads 21 and 22 via agents 41 and 42, and a lid 50 that airtightly seals the crystal element 30 by being bonded to the package 20.

Then, the crystal element 30 includes a crystal piece 35, excitation electrodes 33 and 34 provided on the crystal piece 35, and an extraction electrode 31 drawn from the excitation electrodes 33 and 34 to one side (short side 38) of the crystal piece 35. , 32 and. The electrode pads 21 and 22 fix the crystal element 30 in a cantilever shape by electrically and mechanically connecting to the extraction electrodes 31 and 32 via the conductive adhesives 41 and 42. The conductive adhesives 41 and 42 have a long axis 43 (FIG. 4 [A]) parallel to one side (short side 38) and a short axis 44 (FIG. 4 [A]) perpendicular to one side (short side 38) in a plan view. ]) It has a substantially elliptical shape. The conductive adhesives 41 and 42 have the same shape. The crystal piece 35 may have a rectangular plate shape having a long side and a short side in a plan view, and the excitation electrodes 33 and 34 may be provided on both sides of the crystal piece 35, and the one side may correspond to the short side 38.

Explaining based on FIG. 4 [A], the short side 38 may overlap the long axis 43 in a plan view. The conductive adhesive 41 may be brought into contact with the entire linear portion 31a of the extraction electrode 31 on the short side 38. The same applies to the conductive adhesive 42. When the length (major axis) of the major axis 43 is 2a and the length (minor axis) of the minor axis 44 is 2b, a = 3b may be set. For example, the length of the major axis 43 is 75 to 300 μm, and the length of the minor axis 44 is 25 to 100 μm.

5A and 5B are plan views showing modified examples of the conductive adhesives 41 and 42, FIG. 5 [A] is modified example 1, FIG. 5 [B] is modified example 2, and FIG. 5 [C] is modified example 3. is there. As shown in FIG. 4 [A], the conductive adhesives 41 and 42 are substantially ellipses composed of a long axis 43 parallel to the short sides 38 and 39 and a short axis 44 parallel to the long sides 36 and 37 in a plan view. The shape. The "substantially elliptical shape" here may be any shape having a major axis (length in the longitudinal direction) 43 and a minor axis (length in the lateral direction) 44, for example, a rectangle with rounded apex. (FIG. 5 [A]: conductive adhesive 41a), rhombus with rounded apex (FIG. 5 [B]: conductive adhesive 41b), ellipse asymmetric about the major axis 43 (FIG. 5 [C]). : Conductive adhesive 41c), and combinations thereof are also included.

The ellipse shown in FIG. 5 [C] is composed of two semi-ellipses (conductive adhesives 41d, 41e) having a major axis 43 and different flatness. The flatness f1 of the conductive adhesive 41d is f1 = 1-b / a, and the flatness f2 of the conductive adhesive 41e is f2 = 1-b'/ a. However, b> b', and the minor axis 44'is shorter than the minor axis 44. The smaller the flattening, the closer to a perfect circle, and the larger the flattening, the crushed ellipse. Explaining based on FIGS. 4A and 5C, the conductive adhesive 41e is arranged on the tip end side of the crystal element 30, and the conductive adhesive 41d is arranged on the proximal end side of the crystal element 30. The distance between the adhesive 41c and the excitation electrodes 33 and 34 can be increased.

6A and 6B are plan views showing a method of applying the conductive adhesives 41 and 42. FIG. 6A is a first example, FIG. 6B is a second example, and FIG. 6C is a third example. Is. The dispenser nozzle 81 in the first example has a substantially elliptical discharge port 82 for discharging the liquid conductive adhesive 40. By discharging the conductive adhesive 40 from the discharge port 82 at the center of the electrode pads 21 and 22, the conductive adhesives 41 and 42 having a substantially elliptical shape in a plan view can be obtained. The dispenser nozzle 83 in the second example has a minute circular discharge port 84 for discharging the liquid conductive adhesive 40. When the conductive adhesive 40 is discharged from the discharge port 84 along the long axis 43, the conductive adhesives 41 and 42 having a substantially elliptical shape in a plan view can be obtained by adjusting the discharge amount and the moving speed. ..

In the third example, the electrode pads 21 and 22 are provided with a substantially elliptical adhesive adhesive surface 23 and an adhesive liquid repellent surface 24 composed of other regions. As the adhesive adhesion surface 23, the surface of the electrode pads 21 and 22 may be used as it is. The adhesive liquid-repellent surface 24 imparts the property of repelling the liquid conductive adhesive 40 by providing, for example, a fluorine resin film on the surface of the electrode pads 21 and 22. In the third example, since the adhesive adhesive surface 23 and the adhesive liquid repellent surface 24 are provided on the electrode pads 21 and 22, the conductive adhesive 40 is discharged onto the electrode pads 21 and 22 from a general dispenser nozzle. By doing so, conductive adhesives 41 and 42 having a substantially elliptical shape in a plan view can be obtained.

Next, the configurations of the crystal device 10 and the nozzles 81 and 83 for the dispenser will be described in more detail.

The crystal device 10 is a crystal oscillator including a package 20, a crystal element 30, and a lid 50. The crystal device 10 includes a crystal oscillator with a semiconductor IC chip, a voltage-controlled crystal oscillator (VCXO), a temperature-compensated crystal oscillator (TCXO: Temperature Compensated Crystal Oscillator), or a crystal oscillator with a constant temperature bath (TCXO). OCXO: Oven Controlled Crystal Oscillator) may be used.

The package 20 has a rectangular substrate 25 having an upper surface 25a and a lower surface 25b, a frame body 26 integrated with the peripheral edge of the upper surface 25a, electrode pads 21 and 22 provided on the upper surface 25a, and four corners of the lower surface 25b. It is provided with an external connection terminal 12 provided.

In FIG. 2, a part of the frame body 26 is excised and shown. The frame body 26 has a rectangular frame shape along the peripheral edge of the substrate 25. The substrate 25 is formed with a conductor (not shown) that electrically connects the electrode pads 21 and 22 and the external connection terminal 12. The substrate 25 and the frame body 26 are made of, for example, laminated ceramics. In that case, the substrate 25 and the frame body 26 are obtained by stacking a plurality of square-shaped green sheets, stacking a plurality of square frame-shaped green sheets on the green sheets, and firing the whole.

The electrode pads 21 and 22 are made of a conductor obtained by metallizing, for example, tungsten or the like and plated with gold, and are provided at positions facing the lead-out electrodes 31 and 32 of the crystal element 30. The lead-out electrodes 31 are provided by conductive adhesives 41 and 42. , 32 electrically connected.

The conductive adhesives 41 and 42 are composed of a binder such as a silicone resin containing a conductive powder as a conductive filler (for example, silver paste) and have fluidity before curing. Examples of the curing method include heating and light irradiation. As the conductive powder, one containing any one of aluminum, molybdenum, tungsten, platinum, palladium, silver, titanium, nickel or nickel iron or a combination thereof is used. Further, as the binder, for example, a silicone resin, an epoxy resin, a polyimide resin or a bismaleimide resin is used.

The crystal element 30 has drawer electrodes 31, 32, excitation electrodes 33, 34, and a crystal piece 35. The crystal piece 35 is made of, for example, a rectangular AT cut plate. The excitation electrodes 33 and 34 are provided on both sides of the crystal piece 35 and are insulated from each other. A part of the excitation electrodes 33 and 34 extends from one main surface of the crystal piece 35 across the side surface to the other main surface, and is connected to the extraction electrodes 31 and 32, respectively. The crystal element 30 is a thickness sliding vibration element, but a tuning fork type bending vibration element, a contour sliding vibration element, or the like can be used instead.

The lid 50 is a rectangular flat plate made of metal such as Kovar, and is superposed on the upper end surface 26a of the frame 26 of the package 20. That is, the lid 50 is joined to the package 20 with a sealing material or the like to form an airtightly sealed recessed space 11. The recessed space 11 is formed on the package 20 side in the first embodiment, but may be formed on the lid 50 side.

The electrode pads 21 and 22 fix the crystal element 30 in a cantilever shape by electrically and mechanically connecting to the extraction electrodes 31 and 32 via conductive adhesives 41 and 42, respectively. That is, in the crystal device 10, in a state where the crystal element 30 is mounted on the package 20, the package 20 and the lid 50 are joined by a glass sealing material, a brazing material (neither of them is shown), or the like, and the crystal element 30 is formed. Has an airtightly sealed structure in the recessed space 11.

The dispenser nozzles 81 and 83 are a part of the dispenser and are cylindrical hollow tubes made of metal. For example, a constant amount of the conductive adhesive 40 is discharged by air pressure. The outer shape of the dispenser nozzles 81 and 83 is not limited to a columnar shape or a prismatic shape, and may be, for example, an inverted pyramidal table shape. The dispenser is not limited to the above-mentioned air pressurization type, and may be any type such as a rotary positive displacement type uniaxial eccentric screw pump.

Next, a method of manufacturing the crystal device 10 will be described.

In the manufacturing method of the first embodiment, the extraction electrodes 31 and 32 provided on the crystal element 30 are connected to the electrode pads 21 and 22 provided on the package 20 via the conductive adhesives 41 and 42, and the package 20 is formed. A method for manufacturing a crystal device 10 in which the crystal element 30 is airtightly sealed by the lid 50 and the lid 50, which includes the following steps.

-Adhesive application step: As described above, the conductive adhesives 41 and 42 are applied onto the electrode pads 21 and 22.
-Element mounting step: The drawing electrodes 31 and 32 are mounted on the electrode pads 21 and 22 via the conductive adhesives 41 and 42.
-Adhesive curing step: The crystal element 30 is mounted by curing the conductive adhesives 41 and 42.
-Lid body joining step: The crystal element 30 is hermetically sealed by joining the lid body 50 to the package 20.

Next, the adhesive application step according to the first example shown in FIG. 6 [A] will be described together with FIG. 4 [A] and the like.

First, the dispenser nozzle 81 is positioned above the electrode pad 21, and the dispenser nozzle 81 is lowered toward the electrode pad 21. Subsequently, the dispenser nozzle 81 is stopped immediately before the electrode pad 21, and air pressure is applied to discharge a constant amount of the conductive adhesive 40 from the discharge port 82. Subsequently, when the dispenser nozzle 81 is raised, a certain amount of the conductive adhesive 41 is rounded by surface tension and applied to the electrode pad 21. Subsequently, the dispenser nozzle 81 is moved from above the electrode pad 21 to above the electrode pad 22.

Then, the dispenser nozzle 81 is positioned above the electrode pad 22, and the dispenser nozzle 81 is lowered toward the electrode pad 22. Subsequently, the dispenser nozzle 81 is stopped immediately before the electrode pad 22, and air pressure is applied to discharge a constant amount of the conductive adhesive 40 from the discharge port 82. Finally, when the dispenser nozzle 81 is raised, a certain amount of the conductive adhesive 42 is rounded by surface tension and applied to the electrode pad 22.

The adhesive application step according to the second example shown in FIG. 6 [B] and the third example shown in FIG. 6 [C] is also similar to the adhesive application step according to the first example described above.

Next, the operation and effect of the first embodiment will be described.

The crystal device 70 of Comparative Example 1 shown in FIG. 4 [B] is the crystal of the first embodiment shown in FIG. 4 [A], except that the conductive adhesives 71 and 72 have a circular shape in a plan view. It has the same configuration as the device 10. In Comparative Example 1, in order to increase the contact area between the crystal element 30 and the conductive adhesives 71 and 72, the radius r of the conductive adhesives 71 and 72 applied in a circular shape to the electrode pads 21 and 22 is increased. There is a need to. However, if the radius r of the conductive adhesives 71 and 72 is increased, the conductive adhesives 41 and 42 approach the excitation electrodes 33 and 34, and the vibration of the crystal element 30 is hindered. There was a problem that the equivalent series resistance value became large.

On the other hand, according to the first embodiment shown in FIG. 4A, the conductive adhesives 41 and 42 on the electrode pads 21 and 22 are attached to one side of the crystal piece 35 provided with the extraction electrodes 31 and 32 ( The conductive adhesives 41 and 42 are brought closer to the excitation electrodes 33 and 34 by forming a substantially elliptical shape consisting of a long axis 43 parallel to the short side 38) and a short axis 44 perpendicular to one side (short side 38). Without this, the contact area between the crystal element 30 and the conductive adhesives 41 and 42 can be increased in the long axis 43 direction. Therefore, it is possible to provide the crystal device 10 capable of increasing the contact area between the crystal element 30 and the conductive adhesives 41 and 42 without increasing the equivalent series resistance value of the crystal element 30. Further, since the conductive adhesives 41 and 42 do not approach the excitation electrodes 33 and 34, the excitation electrodes 33 and 34 can be increased by that amount, so that the equivalent series resistance value can be further reduced. It is assumed that the distance between the conductive adhesives 41 and 42 and the excitation electrodes 33 and 34 in the first embodiment is d1, and the distance between the conductive adhesives 71 and 72 and the excitation electrodes 33 and 34 in Comparative Example 1 is d2. d1> d2.

The crystal piece 35 may have a rectangular plate shape having a long side and a short side in a plan view, and the excitation electrodes 33 and 34 may be provided on both sides of the crystal piece 35, and the one side may correspond to the short side 38. In this case, the crystal element 30 can provide the crystal device 10 which is a thickness sliding vibration element.

Explaining based on FIG. 4 [A], the short side 38 may overlap the long axis 43 in a plan view. The contact area between the crystal element 30 and the conductive adhesives 41 and 42 decreases as the short side 38 is moved closer to the excitation electrode 33 than the long axis 43, and conversely, the short side 38 of the excitation electrode 33 is closer to the excitation electrode 33 than the long axis 43. The conductive adhesives 41 and 42 come closer to the excitation electrodes 33 and 34 as they move away from each other. Therefore, by arranging the short side 38 so as to overlap the long axis 43, the crystal element 30 and the conductive adhesive 41, 42 can be attached to each other without bringing the conductive adhesives 41, 42 close to the excitation electrodes 33, 34. The contact area can be surely increased in the direction of the long axis 43.

The conductive adhesive 41 may be brought into contact with the entire linear portion 31a of the extraction electrode 31 on the short side 38. The same applies to the conductive adhesive 42. In Comparative Example 1, the linear portion 31b of the lead-out electrode 31 on the short side 38 is not in contact with the conductive adhesive 71. Therefore, according to the first embodiment, since the fillet of the conductive adhesive 71 can be formed on the entire linear portion 31a of the extraction electrode 31, the connection strength of the crystal element 30 can be improved as compared with Comparative Example 1. Further, when the crystal piece 35 of the AT cut plate is processed by etching with hydrofluoric acid, the contact area between the crystal element 30 and the conductive adhesives 41 and 42 becomes large due to the formation of a residue on the short side 38. Therefore, the connection strength of the crystal element 30 can be further improved.

When the length of the major axis 43 is 2a and the length of the minor axis 44 is 2b, a = 3b may be set. As a is made larger than 3b, the conductive adhesives 41 and 42 become flat and elliptical, so that the contact area between the crystal element 30 and the conductive adhesives 41 and 42 decreases, and conversely, a is 3b. The smaller the size, the closer the conductive adhesives 41 and 42 are to a circular shape, so that the conductive adhesives 41 and 42 approach the excitation electrodes 33 and 34. Therefore, by setting a = 3b, the contact area between the crystal element 30 and the conductive adhesives 41 and 42 is set in the long axis 43 direction without bringing the conductive adhesives 41 and 42 close to the excitation electrodes 33 and 34. You can definitely increase it.

Next, the crystal device of the second embodiment will be described. FIG. 7 is a plan view showing the crystal device of the second embodiment. FIG. 8 is an exploded perspective view showing the crystal device of the second embodiment. FIG. 9 is a sectional view taken along line IX-IX in FIG. Hereinafter, description will be given based on these drawings. In addition, in FIG. 7, the lid body is removed and shown.

The crystal device 60 of the second embodiment is provided on the package 20 on the excitation electrodes 33 and 34 side of the conductive adhesives 41 and 42 or on the electrode pads 21 and 22, and supports the crystal element 30. 62 is further provided. Like the electrode pads 21 and 22, the support bumps 61 and 62 are made of a conductor such as tungsten metallized with gold plating or an insulating material such as ceramics. Molybdenum, copper, silver, or silver-palladium is used in addition to the tungsten, and nickel plating is used in addition to gold plating.

According to the second embodiment, since the support bumps 61 and 62 are provided on the electrode pads 21 and 22, it is possible to prevent the conductive adhesives 41 and 42 from spreading in the excitation electrodes 33 and 34. Further, it is possible to reduce the contact of the tip of the crystal element 30 with the package 20 while ensuring the thickness of the conductive adhesives 41 and 42 in the vertical direction. As a result, it is possible to avoid hindering the thickness sliding vibration and suppress fluctuations in frequency characteristics. In particular, even if the flatness is increased (that is, even if the minor axis is shortened and the major axis is lengthened), the crystal element 30 is supported by the support bumps 61 and 62, so that the stability of the crystal element 30 can be ensured and thus conductive. The contact area between the crystal element 30 and the conductive adhesives 41 and 42 can be reliably increased in the long axis 43 direction without bringing the sex adhesives 41 and 42 close to the excitation electrodes 33 and 34.

In other words, as the distance d1 between the conductive adhesives 41 and 42 and the excitation electrodes 33 and 34 shown in FIG. 4 [A] is increased, the equivalent series resistance value of the crystal element 30 can be reduced, but the conductive adhesive 41 , 42 also increases the distance from the tip of the crystal element 30, which causes a problem that the tip of the crystal element 30 easily comes into contact with the package 20. At this time, this problem can be solved by providing the support bumps 61 and 62. For example, in the shape of the conductive adhesive 41c shown in FIG. 5 [C], it is preferable to provide support bumps 61 and 62. Other configurations, actions and effects of the second embodiment are similar to those of the first embodiment.

Although the present invention has been described above with reference to each of the above embodiments, the present invention is not limited to each of the above embodiments. Various changes that can be understood by those skilled in the art can be made to the structure and details of the present invention. In addition, the present invention also includes a part or all of the configurations of the above-described embodiments appropriately combined with each other.

The present invention can be used for crystal devices such as crystal oscillators and SAW devices that use quartz as a piezoelectric material.

10, 60, 70 Crystal device 11 Recessed space 12 External connection terminal 20 Package 21 and 22 Electrode pad 23 Adhesive adhesion surface 24 Adhesive liquid repellent surface 25 Substrate 25a Top surface 25b Bottom surface 26 Frame body 26a Top surface surface 30 Crystal element 31, 32 Draw-out electrode 31a, 31b Linear part 33,34 Excitation electrode 35 Crystal piece 36,37 Long side 38 Short side (one side)
39 Short sides 40, 41, 41a, 41b, 41c, 41d, 41e, 42, 71, 72 Conductive adhesive 43 Long axis 44, 44'Short axis 50 Lid body 61, 62 Support bump 81, 83 Dispenser nozzle 82 , 84 Discharge port

Claims (5)

Package and
With the electrode pads provided on this package,
With the conductive adhesive provided on this electrode pad,
A crystal element connected to the electrode pad via this conductive adhesive and
It is provided with a lid that airtightly seals the crystal element by being joined to the package.
The crystal element is a rectangular plate-shaped crystal piece composed of a long side and a short side in a plan view , an excitation electrode provided on both sides of the crystal piece, and the short side of one of the crystal pieces from the excitation electrode. Has a lead-out electrode that is pulled out to
The electrode pad fixes the crystal element in a cantilever shape by electrically and mechanically connecting to the extraction electrode via a conductive adhesive.
Said conductive adhesive, Ri substantially elliptical shape der consisting perpendicular short axis to the long axis and the one short side which overlaps a short side of the one in a plan view, the drawer on the short side of the one In contact with the entire linear part of the electrode,
A crystal device that features that. The conductive adhesive is composed of two semi-ellipses having different flatnesses that share the long axis in a plan view, and the one having the larger flatness is in contact with the crystal element. The smaller ones were arranged so as not to touch the crystal element.
The crystal device according to claim 1. An adhesive adhering surface having a substantially elliptical shape and to which the liquid conductive adhesive adheres to the electrode pad, and an adhesive liquid-repellent surface consisting of other regions and to which the liquid conductive adhesive is repelled. Was provided,
The crystal device according to claim 1 or 2. When the length of the major axis is 2a and the length of the minor axis is 2b, a = 3b.
The crystal device according to any one of claims 1 to 3 . A support bump provided on the package or the electrode pad on the excitation electrode side of the conductive adhesive and supporting the crystal element is further provided.
The crystal device according to any one of claims 1 to 4 .