JP2013005203A - Vibration piece, vibrator, oscillator and electronic apparatus - Google Patents

Abstract

A vibrator element that is driven in a stable bending secondary mode is realized.
A resonator element includes a base portion, vibrating arms and extending from a base end portion of a base portion, and excitation electrodes provided on first main surfaces of the vibrating arms. 30 and 40 and the excitation electrodes 38 and 48 provided on the second main surface 10b, and the length Lb from the base end portion 11a of the excitation electrodes 30, 38, 40 and 48 is It is set in the range from the compression displacement to the tensile displacement in the bending secondary mode. In this way, by forming the excitation electrodes 30, 38, 40, 48 in the range from the base end portion 11 a of the vibrating arms 12, 13 to the position of the conversion portion from the compression displacement to the tensile displacement, The generated charges are not canceled by the displacement of the mode vibrating arm, and the excitation efficiency of the bending secondary mode can be increased.
[Selection] Figure 1

Description

  The present invention relates to a resonator element, and a vibrator, an oscillator, and an electronic device having the resonator element.

In addition to those that use the bending primary mode as the fundamental vibration mode in the tuning fork vibrator, in order to realize a vibrator of 100 KHz to several MHz and a high-accuracy coupled oscillator, excitation of the bending secondary mode or higher Some use the next mode. In particular, in order to perform sufficient excitation in the bending secondary mode, the boundary between adjacent excitation electrodes of opposite polarities on the main surface near the two vibrating arms is formed obliquely with respect to the longitudinal direction of the vibrating arm, and There is known a vibrator in which an auxiliary electrode is provided between the respective excitation electrodes on the main surface of the vibrating arm base and the effective excitation electrode length is increased (for example, see Patent Document 1).

JP 59-218042

In Patent Document 1, it is possible to increase the excitation efficiency of the bending secondary mode by increasing the effective excitation electrode length and reducing the CI value (impedance). But,
If the excitation electrode length is 50% or more of the length of the vibrating arm, even if the same potential is applied to the excitation electrode,
Since the polarities of the generated charges are opposite between the base direction and the tip direction of the vibrating arm, the generated potentials cancel each other, and there is a problem that the excitation efficiency of the bending secondary mode is lowered.

The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

Application Example 1 A resonator element according to this application example includes a base, a vibrating arm extending from a base end of the base, and an excitation electrode provided on a main surface of the vibrating arm. The vibrating arm is excited using a bending secondary mode, and the excitation electrode is a conversion portion of the vibrating arm from the compressive displacement to the tensile displacement in the bending secondary mode from the base end or a tensile displacement to a compressive displacement. It is provided within the range up to the conversion part.

The vibration piece according to this application example is a coupled bending vibration piece having a vibration mode of a bending primary mode and a bending secondary mode. Therefore, a bending secondary mode with stable vibration intensity is required. here,
In the bending secondary mode, if the generated charge in the case of compressive displacement is positive, the generated charge in the case of tensile displacement is negative. When the excitation electrode is longer in the tip direction than the aforementioned conversion part, the generated charge polarity is opposite between the base direction and the tip direction of the vibrating arm, so that the charge is canceled and the excitation efficiency of the bending secondary mode is increased. Reduce.
According to this application example, by forming the excitation electrode in the range from the base end portion of the vibrating arm to the position of the conversion portion from the compression displacement to the tensile displacement, the generated charge due to the displacement of the vibrating arm in the bending secondary mode is reduced. There is no cancellation, and the excitation efficiency of the bending secondary mode can be increased.

Application Example 2 In the resonator element according to the application example described above, the length from the base end portion to the tip end of the vibrating arm is La, and the end portion on the opposite side of the base end portion of the excitation electrode from the base end portion. Lb / La is preferably set in a range of 0.1 ≦ Lb / La ≦ 0.46, where Lb is the length up to.

In this way, the excitation electrode is in the length region near the peak value of the charge generated by the compressive displacement, and the distance between the excitation electrode and the conversion portion can be increased, so that the generated charge is canceled by the displacement of the vibrating arm. However, since it becomes more difficult to occur, the excitation efficiency of the bending secondary mode can be further increased.

Application Example 3 In the resonator element according to the application example described above, the length from the base end portion to the tip end of the vibrating arm is La, and the end portion on the opposite side of the base end portion of the excitation electrode from the base end portion. Lb / La is set in the range of 0.16 ≦ Lb / La ≦ 0.28, where Lb is the length up to
Is preferred.

In this way, the length of the excitation electrode is approximately at the peak value of the charge generated by the compression displacement, and the distance between the end portion of the excitation electrode and the above-described conversion portion can be increased, and the excitation electrode is effective for excitation. Since the length can also be secured, it becomes even more difficult to cancel the generated charges due to the displacement of the vibrating arm, so that the excitation efficiency of the bending secondary mode can be further increased.

Application Example 4 In the resonator element according to the application example, a groove portion is provided on the main surface of the vibrating arm,
It is preferable that at least a part of the excitation electrode is provided in the groove.

The vibrating piece is a coupled bending vibrating piece having a bending primary mode and a bending secondary mode,
Fits a resonator element having a resonance frequency of KHz to several MHz. Although the resonance frequency depends on the shape (length, width, thickness) of the vibrating arm, by providing a groove on the vibrating arm, the resonator element can be miniaturized at the same resonance frequency.

Application Example 5 A vibrator according to this application example includes the resonator element according to any one of the application examples described above and a package in which the resonator element is stored.

For example, the resonator element is mounted in a package formed of ceramic or the like. The inside of the package is preferably in a vacuum state, and the vibration piece vibrates in a vacuum environment, so that more stable vibration can be maintained over a long period of time.
Further, since the resonator element is housed in the package, it is easy to handle and can be protected from the external environment such as humidity.

Application Example 6 An oscillator according to this application example includes the resonator element according to any one of the application examples described above and an oscillation circuit connected to the resonator element.

In this way, since the impedance of the secondary mode can be lowered, a stable bending secondary mode excitation strength can be obtained and the oscillator can be downsized.

Application Example 7 An electronic apparatus according to this application example includes the resonator element according to any one of the application examples.

By using the above-mentioned vibrating piece, stabilization of the bending secondary mode can be realized. Therefore, as timing devices, digital mobile phones, personal computers, electronic watches,
Widely used in electronic devices such as video recorders and televisions. The vibrator in which the resonator element is packaged and the oscillator can also vibrate stably and accurately, and can contribute to the quality improvement of the mounted electronic device.

BRIEF DESCRIPTION OF THE DRAWINGS The vibration piece which concerns on Embodiment 1 is represented typically, (a) is a top view, (b) is sectional drawing which shows the AA cut surface of (a), (c) is an electrode structure and connection explanatory drawing. Equivalent circuit of vibrating piece. The vibration form of the resonator element is schematically shown, in which (a) is when the tip of the vibrating arm is displaced away from the central axis P, and (b) is when the tip of the vibrating arm is moved closer. Deformation curve of vibrating arm by simulation. Stress curve of vibrating arm by simulation. The vibration piece which concerns on the modification 1 is shown, (a) is a top view, (b) is sectional drawing which shows the BB cut surface of (a). Sectional drawing which shows the vibrating arm which concerns on the modification 2. FIG. Sectional drawing which shows schematic structure of a vibrator | oscillator. Explanatory drawing which shows the structural example of an oscillator. The perspective view of the mobile telephone shown as an example of an electronic device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings referred to in the following description are schematic views in which the vertical and horizontal scales of each member or part are different from actual ones in order to make each member a recognizable size.
(Embodiment 1)

1A and 1B schematically show a resonator element according to the first embodiment, where FIG. 1A is a plan view, FIG. 1B is a cross-sectional view showing a section AA in FIG. 1A, and FIG. It is explanatory drawing. In addition, this embodiment has illustrated the tuning fork-shaped vibrating piece 10 when a groove part is provided in the vibrating arm. The vibrating piece 10 is
It is developed on a plane composed of an X axis and a Y axis perpendicular to the X axis, and the Z axis represents the thickness. The material of the resonator element 10 may be crystal, a piezoelectric material other than crystal, or other material. In the present embodiment, the crystal resonator element is illustrated, and the X axis is an electric axis, A Z-plate cut from a single crystal of quartz so that the Y-axis is the mechanical axis and the Z-axis is the optical axis, and is a tuning-fork type crystal vibrating piece. It should be noted that each axis, particularly X
What rotated the board | substrate around the axis | shaft etc. may be used. One surface of the resonator element 10 is the first main surface 10a.
The surface facing the first main surface 10a is defined as a second main surface 10b.

The resonator element 10 is provided with a base 11, two vibrating arms 12 and 13 extending in parallel with each other in the Y-axis direction from the base end portion 11 a of the base 11, and protruding on both sides of the base 11 in the X-axis direction. Support arm 14,
15. Note that the length from the base end portion 11a to the tip ends of the vibrating arms 12 and 13 is La.

The first main surface 10a and the second main surface 10b of each of the vibrating arms 12 and 13 are shown in FIGS.
As shown in c), the excitation electrodes 30, 38, 4 from the proximal end portion 11a toward the distal end of the vibrating arm.
0, 48 are provided. Further, as shown in FIGS. 1A and 1B, the excitation electrodes 30 and 3
Grooves 20, 21, 22, and 23 are formed in the formation range of 8, 40, and 48. Excitation electrode 3
0, 38, 40, and 48 are provided on the inner wall surfaces of the grooves 20, 21, 22, and 23, respectively (see FIG. 1C). Therefore, the excitation electrodes 30, 38, 40, and 48 from the base end portion 11a.
The length Lb and the groove length from the base end portion 11a are the same.

Next, the electrode and connection configuration of the resonator element 10 will be described with reference to FIGS. Note that in FIG. 1, electrodes represented by diagonal lines (hatching) in the same direction are represented to have the same potential.
The excitation electrode 30 is formed on the first main surface 10 a of the vibrating arm 12 and is connected to the excitation electrode 38 on the second main surface 10 b side via the lead electrode 31 and side electrodes 32 and 33 provided on the vibrating arm 13. Has been. The lead electrode 31 is branched on the first main surface 10 a of the base 11 and connected to a connection electrode 35 provided at the tip of the support arm 15 via the lead electrode 34.
A lead electrode (not shown) connected to the excitation electrode 38 and the connection electrode 36 are provided on the second main surface 10b side so as to be symmetrical with respect to the lead electrodes 31, 34 and the connection electrode 35, respectively. It has been.

The excitation electrode 40 is formed on the first main surface 10 a of the vibrating arm 13, the side electrodes 42 and 43 provided on the lead electrode 41 and the vibrating arm 12, and the lead electrode 44 provided on the first main surface 10 a of the base 11. Is connected to a connection electrode 45 provided on the support arm portion 14. Further, it is connected to the excitation electrode 48 provided on the second main surface 10 b side through the side electrode 43. The lead electrode (not shown) connected to the excitation electrode 48 and the connection electrode 46 are respectively
It is provided on the second main surface 10 b side so as to be plane-symmetric with respect to the lead electrodes 41 and 44 and the connection electrode 45.

Here, the excitation electrodes 30 and 38 and the excitation electrodes 40 and 48 are connected to the connection electrodes 35 (
Alternatively, when an AC voltage having a reverse polarity is applied via the connection electrode 36) and the connection electrode 45 (or connection electrode 46), the vibrating arms 12 and 13 bend and vibrate in the X-axis direction.

The vibration mode of the resonator element 10 has a combined vibration mode of a bending primary mode and a bending secondary mode. Therefore, in order to stably excite each of the bending primary mode and the bending secondary mode, it is particularly necessary to facilitate the excitation of the bending secondary mode.
This will be described with reference to an equivalent circuit of the resonator element 10.

FIG. 2 shows an equivalent circuit of the resonator element according to this embodiment. Where Cd is the parallel capacitance, L
Reference numeral 1 denotes an equivalent series inductance, C1 denotes an equivalent series capacitance, and R1 denotes an equivalent series resistance. The equivalent series inductance L1, the equivalent series capacitance C1, and the equivalent series resistance R1 are equivalent series components 51 of the bent primary mode. Similarly, L2 is an equivalent series inductance, C2 is an equivalent series capacitance, R2 is an equivalent series resistance, and the equivalent series inductance L2, equivalent series capacitance C2, and equivalent series resistance R2 are equivalent series components of the bent secondary mode. 52.

In each of the bending primary mode and the bending secondary mode, if the impedance is high, excitation is difficult, and if the impedance is low, excitation is easy. Easy to excite. The impedance characteristics depend on the equivalent series capacitances C1 and C2, which depend on the excitation electrode length Lb.
Further, the excitation strength (which can be replaced with the displacement amount) of the vibrating arms 12 and 13 is proportional to the reciprocal of the equivalent parallel capacitance. Therefore, the relationship between the vibrating arm length La and the excitation electrode length Lb will be described.

First, the vibration form of the resonator element 10 will be described.
FIG. 3 schematically shows the vibration form of the resonator element, where (a) is when the tip of the vibrating arm is displaced away from the central axis P, and (b) is when the tip of the vibrating arm is displaced closer. Represents. Note that the vibrating arms 12 and 13 are drawn for easy understanding. And FIG.
The displacement of (a) and the displacement of FIG. 3 (b) are repeated. As shown in FIGS. 3A and 3B, the vibrating arms 12 and 13 vibrate symmetrically with respect to the central axis P of vibration. The vibrating arms 12 and 13 are
It can be seen that the two arms oscillate in combination and have a primary bending mode and a secondary bending mode.

Next, ease of excitation will be described.
FIG. 4 shows a deformation curve of the vibrating arm by simulation. Vibration arm length L on the horizontal axis
The ratio Lb / La of the excitation electrode length Lb with respect to a, and the vertical axis represents the displacement amount of the vibrating arm. The displacement amount is a normalized displacement amount when the displacement amount of the tip of the vibrating arm is fixed to 2 in order to compare the displacement in the bending primary mode and the displacement in the bending secondary mode. The displacement amount shown in FIG. 4 represents the state of FIG. 3A, and the center axis P from the position of the displacement amount 0 (shown by S1 and S2 in the drawing).
The displacement on the side is positive and the displacement on the outside is negative.

In FIG. 4, the amount of displacement in the bending primary mode is Lb / La = from the roots of the vibrating arms 12 and 13.
A gentle curve increases until 1 (the length of the vibrating arm is the same as the length of the excitation electrode). The displacement amount of the bending secondary mode has a peak value near the position of Lb / La = 0.5, and the tip direction (
It gradually decreases toward Lb / La = 1), changes from a positive displacement region to a negative displacement region in the vicinity of Lb / La = 0.8, and further increases the amount of displacement in the negative direction. Here, it is assumed that positive charges are generated in the positive region and negative charges are generated in the negative region. In FIG. 4, the magnitude of the charge amount is not shown.
Therefore, the change in stress with respect to the change in Lb / La is obtained by differentiating the amount of displacement.

FIG. 5 shows a stress curve of the vibrating arm by simulation. Lb / La on the horizontal axis,
The vertical axis represents stress. The stress is expressed as a normalized stress (or a stress reference function) in order to compare the displacement in the bending primary mode and the stress in the bending secondary mode. Here, stress can be described by replacing it with the amount of charge. The positive region is a compressive stress, and the negative region is a tensile stress.
In FIG. 5, the stress in the bending primary mode is Lb / La = 1 from the roots of the vibrating arms 12 and 13.
It increases in a gentle curve until the length of the vibrating arm and the length of the excitation electrode is the same, and compressive stress (positive charge) is generated in the entire area of the curve.

The stress in the bending secondary mode has a peak value in the vicinity of Lb / La = 0.2, and the tip direction (L
It gradually decreases toward b / La = 1), changes from a positive region to a negative region in the vicinity of Lb / La = 0.46, and further increases the displacement in the negative direction. That is, in the bending secondary mode, Lb /
In the vicinity of La = 0.46, the stress is changed from compressive stress to tensile stress. Therefore, Lb / La = 0.4
It can be said that the vicinity of 6 is a conversion part of the polarity of the generated charge.

In the bending secondary mode, the generated charge in the case of compressive displacement is positive, and the generated charge in the case of tensile displacement is negative. Therefore, the excitation electrodes 30, 38, 40, and 48 have the conversion portion (Lb / La
Is longer than ≈0.46), the generated charges have opposite polarities in the base 11 direction and the distal direction of the vibrating arms 12 and 13, so that the charges are offset and the bending secondary mode is excited. Reduce efficiency. Accordingly, by making the length Lb of the excitation electrodes 30, 38, 40, and 48 shorter than the conversion portion, it becomes possible to eliminate the cancellation of the generated charges.

Note that the ratio of the excitation electrode length Lb and the vibrating arm lengths La and Lb is set to 0.1 ≦ Lb / La ≦ 0.46.
It is preferable to set it within the range (shown in FIG. 5, (1)), and 0.16 ≦ Lb / La ≦ 0.
More preferably, it is set in the range of 28 (shown in FIG. 5, (2)).

As described above, the resonator element 10 according to the present embodiment is excited in the range from the base end portion 11a of the vibrating arms 12 and 13 to the position of the conversion portion (Lb / La≈0.46) from the compression displacement to the tensile displacement. By forming the electrodes 30, 38, 40, 48, the generated secondary mode is not canceled by the displacement of the vibrating arm in the bending secondary mode, and the excitation efficiency of the bending secondary mode can be increased.

In addition, by setting the excitation electrode length Lb in a range of 0.1 ≦ Lb / La ≦ 0.46, the excitation electrodes 30, 38, 40, and 48 have a length in the vicinity of the peak value of the charge generated by the compression displacement. Since the distance between the excitation electrodes 30, 38, 40, 48 and the aforementioned conversion portion can be long,
The generated charges due to the displacement of the vibrating arms 12 and 13 are less likely to cancel, and the excitation efficiency of the bending secondary mode can be further increased.

Furthermore, if the excitation electrode length Lb is set to a range of 0.16 ≦ Lb / La ≦ 0.28,
The excitation electrodes 30, 38, 40, and 48 are in the length position of the peak value of the charge generated by the compression displacement. Therefore, the excitation electrodes 30, 38, 40, 48 and the conversion portion (Lb / La≈0.46) described above.
Since the distance between the vibrating arms 12 and 13 can be offset more effectively, the distance between the vibrating arms 12 and 13 can be further reduced. The excitation efficiency of the next mode can be further increased.

In addition, by forming grooves 20, 21, 22, and 23 having the same length as the excitation electrode length Lb in the formation range of the excitation electrodes 30, 38, 40, and 48 in the vibrating arms 12 and 13, the same resonance is achieved. If it is a frequency, the vibration piece 10 can be reduced in size. Such a vibrating piece 10 is
Fits a resonator element having a resonance frequency of 100 KHz to several MHz.

It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
(Modification 1)

6A and 6B show a resonator element according to Modification Example 1, FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view showing a BB cut surface of FIG. Modification 1 is characterized in that an additional electrode is further added to the resonator element 10 of the first embodiment (see FIG. 1). Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals, and different points from the first embodiment will be mainly described. 6A and 6B, an additional electrode 70 is provided on the first main surface 10a of the vibrating arm 12, and an additional electrode 75 is provided on the second main surface. The additional electrode 70 is connected to the excitation electrode 40 via the lead electrode 71, the side electrode 42, and the lead electrode 41. The additional electrode 75 is connected to the additional electrode 70 via side electrodes 73 and 74 and a lead electrode (not shown).

An additional electrode 60 is provided on the first main surface 10a of the vibrating arm 13, and an additional electrode 65 is provided on the second main surface. The additional electrode 60 is connected to the excitation electrode 30 via the lead electrode 61, the side electrode 32, and the lead electrode 31. The additional electrode 65 is connected to the additional electrode 60 via side electrodes 62 and 63 and a lead electrode (not shown).

An insulating layer (for example, SiO ₂ ) is interposed at the intersection between the lead electrode 71 and the lead electrode 64 and at the intersection between the lead electrode 61 and the lead electrode 72 to prevent a short circuit.

In this way, by providing the additional electrodes 60, 65, 70, 75, the parallel capacitance C
d can be increased, and as a result, the impedance (CI value) of the bending secondary mode can be lowered, and the excitation strength of the bending secondary mode can be further increased.
(Modification 2)

Next, Modification 2 will be described. The first embodiment and the first modification described above are the resonator element 10.
The second modification is characterized in that a piezoelectric element and an excitation electrode are provided on the resonator element.
FIG. 7 is a cross-sectional view showing a vibrating arm according to the second modification. A piezoelectric element 80 is provided on the first main surface 10a of the vibrating arm 12, and a piezoelectric element 81 is provided on the second main surface 10b. An excitation electrode 30 is provided on the surface of the piezoelectric element 80, and an excitation electrode 38 is provided on the surface of the piezoelectric element 81. Excitation electrode 3
0 and 38 correspond to the excitation electrodes 30 and 38 described in the first embodiment (see FIG. 1). Also,
Side electrodes 42 and 43 are provided on the side surfaces of the resonating arm 12, and these side electrodes correspond to the side electrodes 42 and 43 described in the first embodiment (see FIG. 1).

An excitation electrode 40 is provided on the surface of the piezoelectric element 82, and an excitation electrode 48 is provided on the surface of the piezoelectric element 83. The excitation electrodes 40 and 48 correspond to the excitation electrodes 40 and 48 described in the first embodiment (see FIG. 1). Further, side electrodes 32 and 33 are provided on the side surface of the vibrating arm 13, and the side electrodes correspond to the side electrodes 32 and 33 described in the first embodiment (see FIG. 1).

Therefore, the length Lb from the base end portion 11a of the excitation electrodes 30, 38, 40, and 48 is formed under the same conditions as the excitation electrode length Lb described in the first embodiment.

In the second modification, the vibration form as shown in FIG. 3 and the vibrating arm 12 as shown in FIG.
, 13 and the stress curves of the vibrating arms 12, 13 as shown in FIG. 5 can be obtained, so that the same effect as in the first embodiment can be obtained.

Moreover, the modified example 2 can be combined with the modified example 1 (see FIG. 6) described above, and an effect obtained by combining the first embodiment and the modified example 1 can be achieved.
(Vibrator)

Next, an example of a vibrator using the above-described vibrating piece 10 will be described with reference to the drawings.
FIG. 8 is a cross-sectional view showing a schematic configuration of the vibrator. The vibrator 100 is the vibrating piece 10 described above.
The main component is a package base 101 that accommodates the resonator element 10 and a lid 102 that seals the opening of the package base 101.

The package base 101 is a box body obtained by laminating and firing ceramic green sheets and the like, and a pedestal 103 for mounting the resonator element 10 and internal mounting electrodes 106 and 107 are formed inside a cavity formed in a concave shape. ing. The internal mounting electrode 106 is electrically connected to the connection electrode 36 of the vibration piece 10, and the internal mounting electrode 107 is electrically connected to the connection electrode 46 of the vibration piece 10. External mounting terminals 104, 1 are provided on the outer bottom surface of the package base 101.
05 is formed. The external mounting terminals 104 and 105 are electrically connected to the internal mounting electrode 106 or the internal mounting electrode 107 through a not-shown through hole or the like.

In the case of the present embodiment, the lid 102 has a flat plate shape, and a metal or glass is often adopted. Whichever material is employed, it is desirable to employ a material whose linear expansion coefficient approximates that of the package base 101.

When sealing the opening of the package base 101 as a package that houses the resonator element 10, the lid 102 is bonded via a bonding material (not shown). The bonding material varies depending on the material constituting the lid 102. For example, when the lid 102 is a metal, a seal ring made of a low melting point metal is used as the bonding material. On the other hand, when the lid 102 is made of glass, it is preferable to use low melting point glass for the joining member.

A space formed by the package base 101 and the lid 102 is hermetically sealed so as to maintain a reduced pressure state or a vacuum state.

In the vibrator 100 configured as described above, the resonator element 10 is excited by an external drive signal via the external mounting terminals 104 and 105, and oscillates at a predetermined frequency (for example, 32 kHz).

The resonator element 10 is housed in a package, and can be maintained in a package in a vacuum environment to maintain a more stable vibration over a long period of time. Further, by being housed in the package, it is easy to handle and the resonator element 10 can be protected from the external environment such as humidity.
(Oscillator)

Next, an oscillator having the above-described resonator element 10 will be described with reference to the drawings.
FIG. 9 is an explanatory diagram illustrating a configuration example of an oscillator. The oscillator 200 includes a resonator element 10 and an oscillation circuit 201 (for example, an inverter) connected in parallel with the resonator element 10. One end of the oscillation circuit 201 is connected to the connection electrode 36 described above, and the other end is connected to the connection electrode 46 described above.
Connected. Further, as illustrated, a capacitive element (capacitor) 202 connected between one connection point of the resonator element 10 and the oscillation circuit 201 and the ground terminal, the resonator element 10, and the oscillation circuit 2.
A capacitive element (capacitor) 203 connected between the other connection point of 01 and the ground terminal;
May be further provided.

The oscillator 200 described above can provide a reduced-size oscillator while maintaining the same performance as the conventional one. Further, by setting Lb / La of the resonator element 10 to an appropriate range as described above, the excitation strength of the bending secondary mode can be increased, and a highly reliable oscillator can be realized.
(Electronics)

Next, an electronic apparatus to which the oscillator 200 having the above-described resonator element 10 is applied will be described.
FIG. 10 is a perspective view of a mobile phone shown as an example of an electronic device. Mobile phone 1000
Is a display unit 1001, a plurality of operation buttons 1002, an earpiece 1003, and a mouthpiece 1004.
And the above-described vibrator 100 or oscillator 200 as a timing device of an internal circuit component. Therefore, a highly reliable mobile phone 1000 including the vibrator 100 or the oscillator 200 as described above can be realized.

The electronic apparatus to which the present invention is applied is not limited to the mobile phone 1000 as described above. For example, an electronic book, a personal computer, a digital still camera, a liquid crystal television, a video tape recorder, a car navigation device, a pager, and an electronic notebook. , Calculators, word processors, workstations, videophones, POS terminals.

DESCRIPTION OF SYMBOLS 10 ... Vibrating piece, 11 ... Base part, 11a ... Base end part, 12, 13 ... Vibrating arm, 30, 38, 40
48 ... excitation electrode, La ... vibrating arm length, Lb ... excitation electrode length.

Claims (7)

The base,
A vibrating arm extending from the base end of the base;
An excitation electrode provided on a main surface of the vibrating arm;
Have
The vibrating arm is excited using a bending secondary mode,
The excitation electrode is provided within a range from the base end portion to the conversion portion from the compression displacement to the tensile displacement or the conversion portion from the tensile displacement to the compression displacement in the bending secondary mode of the vibrating arm;
Vibrating piece characterized by. The length from the base end to the tip of the vibrating arm is La,
When the length from the base end to the end opposite to the base end of the excitation electrode is Lb,
Lb / La is set in a range of 0.1 ≦ Lb / La ≦ 0.46,
The resonator element according to claim 1. The length from the base end to the tip of the vibrating arm is La,
When the length from the base end to the end opposite to the base end of the excitation electrode is Lb,
Lb / La is set in a range of 0.16 ≦ Lb / La ≦ 0.28,
The resonator element according to claim 1. A groove is provided on the main surface of the vibrating arm,
At least a part of the excitation electrode is provided in the groove,
The resonator element according to claim 1, wherein: A vibrating piece according to any one of claims 1 to 4,
A package in which the resonator element is stored;
A vibrator characterized by comprising: A vibrating piece according to any one of claims 1 to 4,
An oscillation circuit connected to the resonator element;
An oscillator comprising: The resonator element according to claim 1, comprising the resonator element according to claim 1.
An electronic device characterized by that.

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