WO2000044092A1

WO2000044092A1 - Vibrator and electronic device with vibrator

Info

Publication number: WO2000044092A1
Application number: PCT/JP2000/000238
Authority: WO
Inventors: Fumitaka Kitamura
Original assignee: Seiko Epson Corporation
Priority date: 1999-01-20
Filing date: 2000-01-19
Publication date: 2000-07-27
Also published as: JP4852195B2; JP2009165164A; JP5013015B2; JP2012039667A

Abstract

A vibrator includes thin vibrating rods having grooves (120a) in their upper and/or lower surfaces, in which electrodes (140a) are formed. This vibrator can be easily machined in a reduced size, and it has a low CI value.

Description

Description Oscillator and electronic equipment with oscillator

The present invention relates to a vibrator, for example, a vibrator such as a tuning-fork type quartz vibrator or a gyro sensor, and an electronic device mounted with the vibrator. Background art

Conventionally, a so-called tuning-fork type crystal resonator, which is a resonator, has been formed, for example, as shown in FIG.

In FIG. 11, the tuning-fork type quartz vibrating piece 10 has, for example, a resonance frequency of 32.768 kHz, which is a high-precision vibrator, and is widely used in watches and other clock-equipped devices. Commonly used.

More specifically, as shown in FIG. 11, the tuning-fork type quartz vibrating piece 10 has a base 11, and the vibrating rod 12 extends upward from the base 11 in the figure. There is a book.

The width of each of the vibrating rods 12 and 12 is usually about 0.23 mm as shown in the figure, and the width of the base 11 is usually about 0.69 mm as shown in the figure. It has become. The total length of the base 11 and the vibrating rod 12 is usually about 3.6 mm as shown in the figure.

In addition, since the vibrating rods 12 and 12 vibrate, as shown in FIG. 12 (FIG. 12 is a schematic cross section taken along line AA ′ of FIG. 11). Electrodes 13 a and 13 b were formed on four sides of 12. That is, the electrodes 13a are arranged on the upper and lower portions of the vibrating rod 12 in the figure, and the electrodes 13b are disposed on both sides 13b, 13b of the vibrating rod 12.

Here, voltages having different polarities are alternately applied to the electrodes 13a and 13b. For example, at one moment, a positive voltage is applied to 13a and a negative voltage is applied to 13b. It is. When a voltage is applied to the vibrating rod 12, an electric field is generated inside the vibrating rod 12, as indicated by an arrow in FIG.

Due to this electric field, the crystal of the vibrating rod 12 expands and contracts, and the vibrating rod 12 vibrates.

The tuning-fork type crystal vibrating piece 10 that vibrates in this manner is housed in a protector (not shown), and is used as a surface mount device (SMD) or the like as an oscillation source of an oscillation circuit such as a clock. As the SMD package in this case, for example, a tuning fork type crystal resonator 10 having a length of about 5 mm in the longitudinal direction and a length of about 2 mm in the short direction is used.

The thickness of the above-mentioned tuning-fork type quartz vibrating piece 10 in the vertical direction in FIG. 12 is about 0.1 mm, and the above-mentioned SMD package is also used for this tuning-fork type quartz vibrating piece 10. It has a thickness corresponding to the thickness.

By the way, such a tuning-fork type crystal vibrating piece 10 has a low CI value (crystal impedance or equivalent) in order to maintain a stable oscillation frequency (for example, 32.768 kHz) and to suppress the vibration loss of the vibrating rod 12. It is necessary to maintain the series resistance (Rr).

On the other hand, watches and electronic devices in recent years have tended to be downsized, and the tuning fork type quartz vibrating piece 10 has also been required to be downsized. In order to reduce the size of the entire tuning-fork type quartz vibrating piece 10, it is necessary to further shorten the vertical dimension 2.4 mm of the vibrating rod 12 in FIG. 11. As described above, when the vibrating rod 12 is shortened, the resonance frequency increases, and the frequency becomes higher than a desired frequency.

For this reason, it was necessary to reduce the width of the vibrating rod 12 (0.23 mm in Fig. 11) to prevent the resonance frequency from rising.

However, when the width of the vibrating rod 12 is reduced in this way, there is a problem that the I value, which is the vibration loss of the vibrating rod 12, increases.

That is, as shown in FIG. 13, when the width of the vibrating rod 22 (in the horizontal direction in the figure) is reduced, the width of the electrode 23a cannot be increased, and the area to which an electric field is applied decreases. In other words, the electric field weakens near its center as compared to Fig. 12. (In the figure, the electric field strength Indicated by the number of marks. In other words, it indicates that the electric field intensity increases as the number of arrows increases. )

Therefore, the electric field (arrow in the figure) generated between the electrode 23a and the electrode 23b is not distributed over the entire vibrating rod 22 as shown in FIG. The same vibration as in (2) does not occur, but becomes smaller.

On the other hand, in order to prevent the CI value, which is the vibration loss, from rising, it is necessary to further reduce the thickness of the tuning-fork type quartz vibrating piece 10 shown in FIG. 12 in the vertical direction, for example, about 0.1 mm. However, in this case, processing became extremely difficult, and the yield of the product deteriorated.

In view of the above, an object of the present invention is to provide a small-sized vibrator in which the CI value is suppressed to a low value and which is easy to process. Disclosure of the invention

According to the first aspect of the present invention, there is provided a vibrator having a vibrating rod made of at least one or more piezoelectric materials, wherein a groove is formed on one or both of a front surface and a back surface of the vibrating rod. This is achieved by a vibrator characterized in that a groove is formed and an electrode is formed in this groove.

According to the configuration, a groove is formed on one or both of the front surface and the back surface of the vibrating rod, and an electrode is formed in the groove, so that processing is easy. However, the vibrating rod is uniformly and strongly distributed in the depth direction, so that an increase in CI value can be suppressed.

Preferably, according to the second aspect of the present invention, in the configuration of the first aspect, the vibrator is a tuning-fork type quartz vibrator.

According to the configuration, in the tuning-fork type quartz resonator, an electric field generated from the electrode disposed on the vibrating rod is widely distributed on the vibrating rod, and an increase in CI value can be suppressed.

According to the third aspect of the present invention, there is provided a vibrator having a plurality of vibrating rods, wherein a groove is formed on a first surface and a second surface of the vibrating rod. A first electrode is formed on at least a part of the groove, and a second electrode is formed on at least a part of a surface of the vibrating rod other than the surface on which the groove is formed. This is achieved by the oscillator.

According to the above configuration, since the groove is formed on the first surface and the second surface of the vibrating rod, and the first electrode is formed on at least a part of the groove, the vibrating rod is formed. An electric field generated between a second electrode formed on at least a part of a surface other than the surface on which the groove is formed and a first electrode of the groove is formed in the depth direction of the vibrating rod. And the distribution is strong and constant, and the rise of the CI value of the vibrating rod of the vibrator can be suppressed. Preferably, according to the invention of claim 4, in the configuration of claim 3, the first electrode is formed at least near a root of the vibrating rod. It is.

According to the configuration, since the first electrode is formed at least near the root of the vibrating rod, an electric field required to vibrate the vibrating rod can be obtained. Preferably, according to the invention of claim 5, in the configuration of claim 3, the first electrode is a vibrator formed only on a side surface of the groove. Further, preferably according to the invention of claim 6, in the configuration of claim 3, there is provided a vibrator in which a through hole is formed in a part of the groove.

According to the invention set forth in claim 7, in the configuration according to claim 3, the relationship between the width of the vibrating rod and the thickness of the vibrating rod is 0.6 x ( The vibrator is set as follows: (the vibrating rod) ≤ (width of the vibrating rod).

According to the above configuration, the relationship between the width of the vibrating rod and the thickness of the vibrating rod is set as 0.6 x (the vibrating rod) ≤ (the width of the vibrating rod). Therefore, unlike the conventional configuration of (1.0 X thickness of vibrating rod, width of vibrating rod), the width of the vibrating rod can be made sufficiently smaller than the thickness of the vibrating rod. In addition, the size of the entire vibrator can be reduced.

Further, according to the invention set forth in claim 8, in the configuration set forth in claim 3, the vibrator is formed such that each of the vibrating fine rods has substantially the same structure.

According to the configuration, each of the vibrating rods is formed to have substantially the same structure. Thus, vibration leakage can be prevented and a highly accurate vibrator can be obtained.

According to a ninth aspect of the present invention, in the configuration according to the third aspect, there is provided a vibrator in which the second electrode is formed on a plurality of surfaces.

According to the tenth aspect of the present invention, in the configuration of the third aspect, a third electrode for connecting the second electrode t is formed on the first surface. This is a vibrator.

According to the invention of claim 11, in the configuration of claim 3, a third electrode for connecting the second electrodes is formed on the second surface. This is a vibrator.

According to the invention of claim 12, in the configuration of claim 3, a third electrode for connecting the second electrodes to each other is provided on a surface of a tip end of the vibrating rod. This is a vibrator formed.

According to the invention of claim 13, in the configuration of claim 3, the frequency of the vibrator is set in a range of 1 KHz to 200 KHz by a vibrator. is there.

Further, according to the invention of claim 14, in the configuration of claim 13, the vibration wherein the frequency of the vibrator is set in a range of 16 KHz to 120 KHz. I am a child.

According to the invention of claim 15, in the configuration of claim 14, the vibrator wherein the frequency of the vibrator is set in a range of 16 KHz to 33 KHz. It is.

According to the invention of claim 16, in the configuration according to any one of claims 3 to 12, the first electrode, the second electrode, or the second electrode. The vibrator has an insulating film formed on the surface of the third electrode.

According to the configuration, an insulating film is formed on a surface of the first electrode, the second electrode, or the third electrode. Therefore, even if the entire vibrator is downsized, the first electrode is formed. The pole, the second electrode, or the third electrode can be prevented from being short-circuited by a foreign substance or the like. According to the invention of claim 17, according to the configuration of claim 16, the insulating film is a vibrator made of an oxide film or a nitride film.

According to the above configuration, since the insulating film is made of an oxide film or a nitride film, the first electrode, the second electrode, or the third electrode may be exposed to foreign matter even if the entire vibrator is downsized. Can be prevented.

The object is, according to the invention of claim 18, a vibrator formed by a plurality of vibrating fine rods, wherein a through hole is formed in a part of the vibrating fine rod; This is achieved by a vibrator in which a first electrode is formed on at least a part of the vibrating bar, and a second electrode is formed at least on a surface of the vibrating fine bar facing the first electrode.

According to the invention of claim 19, in the configuration of claim 18, the relationship between the width of the vibrating rod and the thickness of the vibrating rod is 0.6 x (the The vibrator is configured such that the thickness of the vibrating rod is ≤ (the width of the vibrating rod).

According to the configuration, the relationship between the width of the vibrating rod and the thickness of the vibrating rod is set as 0.6 x (thickness of the vibrating rod) ≤ (width of the vibrating rod). In contrast to the conventional configuration (1.0 X thickness of the vibrating rod and width of the vibrating rod), the width of the vibrating rod is sufficient for the thickness of the vibrating rod. Since it can be made small, the whole vibrator can be downsized.

Further, according to the invention of claim 20, in the configuration of claim 18, the vibrator is formed by each of the vibrating fine rods having substantially the same structure.

According to the configuration, since each of the vibrating rods is formed to have substantially the same structure, vibration leakage can be prevented, and a highly accurate vibrator can be obtained.

According to the invention of claim 21, the object has a rectangular coordinate system in which an electric axis is an X axis, a mechanical axis is a Y axis, and an optical axis is a Z axis, and the X axis and the Y axis are A vibrator in which a base is formed and a plurality of vibrating rods are arranged from the base along the Y-axis, wherein a first surface and a second surface of the plurality of vibrating rods are provided. A vibrator having a groove formed on the surface of the groove, a first electrode formed on at least a part of the groove, and a second electrode formed on a surface other than the surface on which the groove is formed; To Is achieved.

According to the configuration, a groove is formed on the first surface and the second surface of the plurality of vibrating rods, and a first electrode is formed on at least a part of the groove. Since the second electrode is formed on a surface other than the surface on which the portion is formed, a gap between the second electrode provided on the vibrating rod of the high-precision vibrator and the first electrode of the groove is provided. The electric field generated by the vibration is uniformly and strongly distributed in the depth direction of the vibrating rod, and it is possible to suppress an increase in the CI value of the vibrating rod of the vibrator with high precision.

According to the invention of claim 22, in the configuration of claim 21, a cross section of the vibrating rod in a plane formed by the X axis and the Z axis is substantially H-shaped. This is a vibrator formed on the substrate.

According to the configuration, the vibrating rod has a substantially H-shaped cross section in a plane formed by the X axis and the Z axis. Therefore, the first electrode and the second electrode of the groove portion are formed. The electric field generated therebetween can be uniformly and strongly distributed in the depth direction by the vibrating rod.

According to the invention of Claim 23, in the configuration of Claim 21, the first surface and the second surface are formed by the X axis and the Y axis. A vibrator that is a surface.

According to the invention of Claim 24, in the configuration of Claim 21, when the Z axis is the thickness of the vibrator, the thickness of the vibrator and the thickness of the vibrating rod are reduced. The transducers have almost the same width.

According to the invention of claim 25, in the configuration of claim 21, the first electrode and the second electrode are formed by stacking a plurality of layers formed of different materials. This is a vibrator, which is a laminated film formed.

According to the above configuration, since the first electrode and the second electrode are a laminated film in which a plurality of layers formed of different materials are laminated, adhesion between these laminated layers is improved. Can be increased.

According to the invention of Claim 26, in the configuration of Claim 21, the vibrator comprising an oxide film formed on a surface of the first electrode and the second electrode. so is there.

According to the configuration, since an oxide film is formed on the surfaces of the first electrode and the second electrode, even if the entire vibrator is downsized, the first electrode and the second electrode In other words, it is possible to prevent the third electrode from being short-circuited by a foreign substance or the like.

According to the invention of claim 27, in the constitution of claim 25, the first electrode and the second electrode are formed of chromium, gold, aluminum, nickel, or titanium. A vibrator formed by any one of the above.

Further, according to the invention of claim 28, there is provided an electronic device equipped with the vibrator according to any one of claims 1 to 27. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a vibrator according to a first embodiment of the present invention. FIG. 2 is a sectional view of a vibrating rod of the vibrator of FIG.

FIG. 3 is a perspective view of a tuning-fork type crystal resonator without electrodes according to the second embodiment. FIG. 4 is a tuning fork-type crystal resonator in which electrodes are attached to the tuning-fork type crystal resonator of FIG. FIG. 3 is a perspective view of a crystal resonator.

FIG. 5 is a diagram showing dimensions and the like of the tuning-fork type quartz resonator of FIG.

FIG. 6 (a) is a cross-sectional view showing the arrangement of the vibrating rods and electrodes of the tuning-fork type quartz resonator of FIG.

FIG. 6 (b) is a cross-sectional view different from FIG. 6 (a) and showing an example of an arrangement state of another electrode.

FIG. 6 (c) is a cross-sectional view showing an example of an arrangement state of another electrode, which is different from FIGS. 6 (a) and (b).

FIG. 7 is a schematic sectional view showing the arrangement of a vibrating rod having a through hole and electrodes.

FIG. 8 is a diagram showing a relationship between a groove in a tuning-fork type quartz resonator and atmospheric CI. FIG. 9 is a perspective view showing another example of groove formation.

FIG. 10 is a sectional view showing an example in which the number of grooves formed in the vibrating rod is increased. FIG. 11 is a diagram showing dimensions and the like of a conventional vibrator.

FIG. 12 is a cross-sectional view of a vibrating rod of a conventional vibrator.

FIG. 13 is a cross-sectional view showing a state in which the width of the vibrating rod of the conventional vibrator is reduced. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)

FIG. 1 is a diagram showing a vibrator according to a first embodiment of the present invention. FIG. 1 shows the appearance of a tuning-fork type vibrator 100 made of a 32 KHz crystal used for a watch as an example. The vibrator 100 is generally composed of two vibrating fine rods 120 and a fixed part 130 as a base.

The fixing portion 130 is provided for fixing to a package and forming a pad portion for taking out an electrode to the outside.

The two vibrating rods 120 vibrate in a direction in which they approach or move away from each other. A groove 120a is formed on one or both of the front and back surfaces of the vibrating rod 120. As a method for forming the groove 120a, processing using photolithography using an etching liquid capable of dissolving the material of the vibrator 100 is used. A crystal resonator can be processed with a hydrofluoric acid-based etching solution.

In FIG. 1, the groove 120a is formed to a part of the fixed portion 130, but this is not limited depending on the characteristics of the vibrator 100 and the processing process. Although the length of the groove 120a is set, the CI value is reduced by providing the groove 120a over the entire length of the vibrating rod 120 as long as possible. However, since the interelectrode capacitance increases, the length of the groove 120a is adjusted according to the specifications of the vibrator. In addition, if it is necessary to adjust the frequency by attaching a weight material to the tip of the vibrating rod 120, or to adjust the frequency, etc. There is no need to provide 0a.

Here, the reason why the characteristics are improved by providing the groove 120a will be described. FIG. 2 is a cross-sectional view of vibrating rod 120 in vibrator 100 according to the present embodiment. In the vibrating rod 120 according to the present embodiment, the electric field 160 is distributed over the entire vibrating rod 120 in the depth direction. That is, since the electrode 140a is formed into the groove 120a, the electric field 160 is easily distributed in the depth direction. In this case, the depth of the groove 120a is better.

When the vibrating rod is a 100-micrometer tuning-fork vibrator and the thickness of the substrate (fixed part and vibrating rod) is 100 micrometers, the equivalent series resistance (CI value) was measured at atmospheric pressure. However, it was 1 gigaohm. The tuning-fork type vibration according to the present embodiment in which the edge of the vibrating rod 120 is left at 15 micrometer and the depth 120 micrometer groove 120 is formed on both surfaces of the vibrating rod 120 For element 100, the equivalent series resistance (CI value) in the atmosphere was 600 kOhm, indicating that it had the same characteristics as a normal tuning fork resonator.

If the electrode 140a can be formed in the entire depth direction, the groove 120a may be connected on the front surface and the back surface. That is, a structure in which a slit is inserted in the vibrating rod 120 may be used.

As described above, according to the present embodiment, it is possible to supply a vibrator having good characteristics without reducing the thickness of vibrator 1 • 0. Furthermore, since the thickness is not different from the conventional one, it is easy to handle and has an effect that the yield does not decrease. And, a small and inexpensive vibrator 1 • 0 can be supplied.

(Second embodiment)

FIG. 3 is a schematic perspective view showing a tuning-fork type quartz crystal resonator 200 according to the second embodiment without electrodes.

The tuning-fork type crystal resonator 200 is formed by cutting out, for example, a single crystal of quartz and applying it to a tuning-fork type. At this time, the crystal is cut from a single crystal of crystal such that the X axis shown in FIG. 3 is the electric axis, the Y axis is the mechanical axis, and the Z axis is the optical axis. By arranging the electric shaft in the X-axis direction in FIG. 3, a tuning fork type crystal resonator 200 suitable for a watch and a general device with a watch requiring high accuracy is obtained.

When cutting from a single crystal of quartz, in the orthogonal coordinate system consisting of the X, Y, and Z axes described above, the XY plane consisting of the X and Y axes is rotated about Every time The tuning-fork type crystal resonator 200 is formed as a so-called crystal Z plate inclined by 5 to 5 degrees.

This tuning-fork type crystal resonator 200 is similar to the tuning-fork type resonator 100 according to the first embodiment described above, and has a fixed portion 230 as a base and a fixed portion 230 from the fixed portion 230. In the figure, for example, there are two vibrating fine rods 220 formed so as to protrude in the Y-axis direction. Further, grooves 220a are formed on the first and second surfaces of the two vibrating rods 220, respectively, as shown in FIG.

As shown in FIG. 4, the thus formed tuning-fork type quartz crystal resonator 200 shown in FIG. 3 has an electrode 240 a as a first electrode and an electrode 240 a as a second electrode. 40b, and the electrode 240c as the third electrode will be arranged. That is, when arranging the electrodes from the fixed portion 230 to the vibrating rod 22 °, the electrodes are placed on the side surfaces of the vibrating rod 220 and the first and second surfaces, respectively, with electrodes 240b, 240 a is provided. Further, the electrode 240 a is also provided inside the groove 220 a of the vibrating rod 220 such an electrode 240 a, 240 b is provided with the electrode 240 a, It is provided for generating an electric field between 240 b and vibrating the vibrating fine rod 220 as a piezoelectric body. Further, the electrode 240c is provided for connecting the second electrodes formed on the two side surfaces of the vibrating rod 220, that is, the electrodes 240b.

Each of the electrodes 240a, 240b, and 240c is formed of a plurality of layers, for example, two layers, and is formed of Cr as a base and Au as an upper layer. In this case, Ni or Ti may be used instead of Cr.

Also, the electrodes 240a, 240b, and 240c may be composed of one layer, and in this case, for example, the A1 layer is used. In addition, an electrode whose surface is anodically oxidized with an A1 electrode, or an electrode in which a Cr electrode is used and an SiO 2 layer or the like is formed as a protective film on this Cr layer can also be used.

In the present embodiment, the electrode 240a is provided inside the groove 220a as shown in FIG. 4, but is not limited to this, and is divided into a plurality of portions of the groove 220a. It may be arranged, or may be formed only on the side surface or bottom surface of the groove 220a. Further, the electrode 24 Ob is disposed on the side surface of the vibrating rod 220 as shown in FIG. 4, but is not limited to this, and as shown in FIG. May be formed on a plurality of surfaces of the vibrating rod 220.

The tuning-fork type crystal resonator 200 formed as described above has a smaller size than a conventional 32.768-kHz tuning-fork type crystal resonator, for example, despite its resonance frequency of 32.768 kHz. Has become. For example, it is configured as shown in FIG.

That is, the length of the tuning-fork type crystal unit 200 shown in FIG. 5 in the Y-axis direction is, for example, about 2.2 mm, and the width of the tuning-fork type crystal unit 200 in the X-axis direction is about 0. It is about 56mm. This dimension is significantly smaller than the dimensions of the conventional tuning-fork type quartz vibrating piece 10 shown in FIG. 10, which are 3.6 mm (Y-axis direction) and 0.69 mm (X-axis direction).

Further, the length of the vibrating rod 220 shown in FIG. 5 in the X-axis direction is, for example, about 1.6 mm, and the width of each vibrating rod 220 in the X-axis direction is, for example, about 0.1 mm. It has become. The size of the vibrating rod 220 is significantly smaller than the dimensions of the vibrating rod 12 shown in FIG. 10, which are 2.4 mm (Y-axis direction) and 0.23 mm (X-axis direction). I have.

On the other hand, the thickness of the tuning-fork type crystal unit in the Z-axis direction of the tuning-fork type crystal unit 200 is, for example, about 0.1 mm, which is equivalent to the thickness of the conventional tuning-fork type crystal unit 200. It is almost the same. However, the groove 220a is formed in the vibrating rod 220 of the tuning-fork type crystal resonator 200 according to the present embodiment, as described above. For example, it is formed to have a length of about 1.3 mm in the axial direction. As shown in FIG. 5, the width of the groove 220a in the X-axis direction is, for example, about 0.07 mm, and the depth in the Z-axis direction is, for example, about 0.02 mm.

Further, the thickness of the electrodes 240a, 240b, 240c arranged in such a small tuning-fork type quartz resonator 200 is, for example, 100 A for the lower layer Cr and 1000 A for the upper layer Au.

Next, a cross section of the vibrating rod 220 of the small tuning-fork type crystal resonator 200 described above is shown. Figure 6 (a) shows the result. As shown in FIG. 6 (a), the grooves 220a are provided in the vertical direction in the figure on the vibrating rod 220, respectively, so that the cross-sectional shape thereof is substantially H-shaped. The electrodes 240a are provided in the grooves 220a at these two places. Electrodes 240b are provided on both sides of the vibrating rod 220, respectively.

The electrodes 240a and 240b are connected to a power source (not shown), and the electrodes 240a and 240b alternately have voltages having different polarities. Is applied. Then, for example, when a positive voltage is applied to the electrode 240a and a negative voltage is applied to the electrode 240b, an electric field is generated as shown by an arrow in FIG. 2 of the first embodiment. Will be.

The generation of this electric field causes the vibrating rod 220 to vibrate, and is used as a component of the oscillation source of, for example, a mobile phone or an IC card in which the tuning-fork type crystal resonator 220 is used.

It should be noted that the arrangement of the electrodes 240a and 240b with respect to the vibrating rod 220 as described above is not limited to the embodiment shown in FIG. 6 (a), but also to the arrangement shown in FIG. 6 (b). Or as shown in Fig. 6 (c).

Further, in the present embodiment, groove 220 a is provided in vibrating rod 220, but this is not restrictive, and groove 220 a may be a through hole. In this case, the vibrating fine rod 220 ′ having a through hole has a configuration in which, for example, electrodes 240a and 240b are arranged to face each other as shown in FIG. FIG. 7 is a schematic view showing a cross section of a vibrating rod 220 ′ having a through hole.

Further, in this case, the electrode 240a may be arranged in all of the through holes. Alternatively, the electrode 240a may be arranged in a plurality of places of the through hole. .

By the way, as described above, when the length of the vibrating rod 220 in the Y-axis direction is shortened with the downsizing of the tuning-fork type crystal resonator 200, the resonance frequency becomes higher, and the stable resonance frequency becomes higher. In order to prevent this, it is necessary to reduce the width of the vibrating rod 220 in the X-axis direction. However, the width of this vibrating rod 2 In this case, the electrode 23 b cannot be made large as shown in FIG. 12, so that the electric field generated between the electrode 23 a and the electrode 23 b is strong and constant in the depth direction of the vibrating rod 22. It was not distributed, and the intensity of the electric field was reduced. As a result, the vibration of the vibrating rod 22 was weakened and the vibration loss was increased.

This vibration loss is indicated by the C I value (crystal impedance or equivalent series resistance R r). The C I value of an ordinary tuning-fork type crystal resonator is preferably from 301 to 60 1 <0 in a vacuum, and is about 400 Ω when the C I value in the atmosphere is shown as a reference value. The CI value of the tuning fork type crystal resonator 200 according to the present embodiment in the case where the groove 220 is not provided in the vibrating rod 220 of the tuning fork crystal resonator 200 is 100 in air as shown in FIG. 0 ΚΩ, which is much higher than the above-mentioned reference value of 400 Ω.

For this reason, simply miniaturized tuning-fork type quartz resonators had excessively high CI values, making them unsuitable for use in oscillators such as mobile phones and IC cards.

However, in the present embodiment, as shown in FIG. 8, the depth of the groove 220a was set to 0.02 mm (20 jm), so that the CI value was 42.5 ΩΩ, Since the value is close to the preferred value of 400 Κ Ω, the CI value stays within the appropriate range, making it suitable for use in oscillators for mobile phones and IC cards. In addition, forming the groove 220a in the vibrating rod 220 in this way is much more excellent in terms of additivity than when the thickness of the vibrating rod 220 is reduced. Thus, the yield of the manufactured tuning-fork type crystal resonator 200 is improved.

In the present embodiment, the depth of the groove 220a is set to 0.02 mm in consideration of the ease of processing and the like, but as is clear from the table of FIG. As the depth of “a” is deeper, the CI value is lower, and at least at a depth of 0.035 mm, the value is 3333ΚΩ. In this case, the C I value at least in vacuum was 40 ΚΩ.

As described above, in this embodiment, the vibrating rod 2 220 is provided with the grooves 220 a and 220 a of two places, and the electrodes 240 a are arranged respectively. Unlike the electrode 23 a of the conventional vibrating rod 220, the electrode 240 a can be arranged larger, so that an electric field is applied to the vibrating rod 2 as shown in FIG. 2 of the first embodiment. It is distributed uniformly and strongly in the depth direction of 20 and vibration loss can be kept low. This reduction in vibration loss Is also evident from the CI values shown in FIG.

In this embodiment, the groove 220 a is provided only in the vibrating rod 220 as shown in FIG. 6 (a). However, as shown in FIG. A groove 320a may be formed over the fixing portion 330. In this case, since the stress due to vibration can be confined in the groove 320a, when the vibrator is fixed, the fluctuation of the frequency can be suppressed.

As described above, the 32.768 kHz tuning-fork type crystal resonator 200 with a CI value within the appropriate range 200, 300 is packaged in a small package, for example, 3.2 mm (Y-axis direction), 1 6 mm (X-axis direction) 0.9 mm (Z-axis direction) makes it possible to use it for small mobile phones and IC cards.

Further, in the present embodiment, the description has been given by taking as an example a tuning fork type crystal resonator 200 of 32.738 kHz, but a tuning fork type crystal resonator of 15 kHz to 150 kHz is described. Clearly, it is applicable.

Further, in the present embodiment, the case where two grooves 220a are formed in the vibrating rod 220 as shown in FIG. 6 has been described. However, as shown in FIG. Two grooves may be provided above and below 420, and electrodes 44a may be arranged in each of them.

The tuning-fork type resonator 100 and the tuning-fork type crystal resonator 200 according to each of the above-described embodiments can be used not only for small mobile phones and IC cards but also for other electronic devices such as gyros and mobile information. It is clear that the present invention can be used for terminals, televisions, video equipments, so-called boomboxes, personal computer built-in clocks, and clocks.

As described above, according to the present invention, it is possible to provide a small-sized vibrator in which the CI value is suppressed to be low and the processing is easy. Industrial applicability

As described above, the present invention is suitable for use as a vibrator, for example, a vibrator such as a tuning-fork type crystal vibrator or a gyro sensor, and an electronic apparatus equipped with the vibrator.

Claims

The scope of the claims

I. A vibrator having at least one vibrating rod made of a piezoelectric material, wherein a groove is formed on one or both of a front surface and a back surface of the vibrating rod, and the groove is formed in the groove. A vibrator having electrodes formed thereon.

2. The vibrator according to claim 1, wherein the vibrator is a tuning-fork type crystal vibrator.

3. A vibrator having a plurality of vibrating rods, wherein a groove is formed on a first surface and a second surface of the vibrating rod, and a first electrode is provided on at least a part of the groove. A vibrator, wherein a second electrode is formed on at least a part of a surface of the vibrating rod other than the surface on which the groove is formed.

4. The vibrator according to claim 3, wherein the first electrode is formed at least near a root of the vibrating rod.

5. The vibrator according to claim 3, wherein the first electrode is formed only on a side surface of the groove.

6. The vibrator according to claim 3, wherein a through hole is formed in a part of the groove.

7. The relationship between the width of the vibrating rod and the thickness of the vibrating rod is set such that 0.6 X (thickness of the vibrating rod) ≤ (width of the vibrating rod). 4. The vibrator according to claim 3, wherein:

8. The vibrator according to claim 3, wherein the vibrating rods have substantially the same structure.

9. The vibrator according to claim 3, wherein the second electrode is formed on a plurality of surfaces.

10. The vibrator according to claim 3, wherein a third electrode for connecting the second electrodes is formed on the first surface.

II. A third electrode for connecting the second electrodes to each other is formed on the second surface. 4. The vibrator according to claim 3, wherein:

12. The vibrator according to claim 3, wherein a third electrode for connecting the second electrodes is formed on a surface of a tip of the vibrating rod.

13. The vibrator according to claim 3, wherein a frequency of the vibrator is set in a range of 1 KHz to 200 KHz.

14. The vibrator according to claim 13, wherein the frequency of the vibrator is preferably set in a range from 16 KHz to 120 KHz.

15. The vibrator according to claim 14, wherein the frequency of the vibrator is preferably set in a range of 16 KHz to 33 KHz.

16. The method according to claim 3, wherein an insulating film is formed on a surface of the first electrode, the second electrode, or the third electrode. A vibrator according to any of the above.

17. The resonator according to claim 16, wherein said insulating film is made of an oxide film or a nitride film.

18. A vibrator formed by a plurality of vibrating rods, wherein a through hole is formed in a part of the vibrating rod, and a first electrode is formed in at least a part of the through hole. A vibrator characterized in that at least a second electrode is formed on a surface of the vibrating rod facing the first electrode.

19. The relationship between the width of the vibrating rod and the thickness of the vibrating rod is set such that 0.6 x (thickness of the vibrating rod) ≤ (width of the vibrating rod). 19. The vibrator according to claim 18, wherein:

20. The vibrator according to claim 18, wherein the vibrating rods are formed in substantially the same structure.

2 1. It has an orthogonal coordinate system in which the electric axis is the X axis, the mechanical axis is the Y axis, and the optical axis is the Z axis, and a base is formed on the surface formed by the X axis and the Y axis, A vibrator in which a plurality of vibrating rods are arranged from the base along the Y axis, wherein a groove is formed on a first surface and a second surface of the plurality of vibrating rods; A first electrode is formed at least partially, and the first electrode is formed on a surface other than the surface on which the groove is formed. A vibrator characterized in that two electrodes are formed.

22. The vibrator according to claim 21, wherein the vibrating rod has a substantially H-shaped cross section in a plane formed by the X axis and the Z axis.

23. The vibrator according to claim 21, wherein the first surface and the second surface are surfaces formed by the X axis and the Y axis.

24. The vibrator according to claim 21, wherein when the Z axis is the thickness of the vibrator, the thickness of the vibrator and the width of the vibrating rod are substantially the same. .

25. The method according to claim 21, wherein the first electrode and the second electrode are laminated films formed by laminating a plurality of layers formed of different materials. The pendulum.

26. The vibrator according to claim 21, wherein an oxide film is formed on surfaces of the first electrode and the second electrode.

27. The vibration according to claim 25, wherein the first electrode and the second electrode are formed of any one of chromium, gold, aluminum, nickel, and titanium. Child.

28. An electronic device comprising the vibrator according to any one of claims 1 to 27 mounted thereon.