JP2014192672A - Bending vibration piece, vibration device, electronic equipment, and moving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bending vibration piece, a vibration device, electronic equipment, and a moving body, for reducing vibration leakage of a vibration arm.SOLUTION: A bending vibration piece 10 includes a base part 20, a first vibration arm 30 extending from one end 22 side of the base part, a second vibration arm 30 which is beside the first vibration arm 30 in top view and extends from the one end 22 side, and a support arm 40 which is positioned between the vibration arm 30 and the second vibration arm 30, to extend from the one end 22 side of the base part 20. On another end 24 side of the base part 20, a projection 50 is provided on both sides of a center line respectively, being a border, of the support arm 40 running along the extension direction of the support arm 40, within a range from an intersection with an extension line of a side surface on the support arm 40 among side surfaces spreading in the extension direction of the first vibration arm 30, to an intersection with the extension line of the side surface of the support arm 40 side among side surfaces spreading in the extension direction of the second vibration arm 30.

Description

  The present invention relates to a bending vibration piece having a pair of vibrating arms, a vibrating device including the bending vibration piece, an electronic apparatus, and a moving body.

Bending vibration pieces using piezoelectric materials are widely used in communication devices such as portable terminals, information devices such as personal computers, and various other electronic devices.
In general, a tuning fork type bending vibration piece that vibrates in a bending vibration mode has a structure in which grooves are formed in the longitudinal direction of the front and back surfaces of a vibrating arm and an excitation electrode is formed on the inner main surface side in order to suppress the CI value. Widely adopted.

  Further, a tuning fork-type bending vibration piece having a structure in which a support arm extending in parallel with the vibrating arm from the base is provided in a frame shape and fixedly supported by the support arm is known. This tuning fork-type flexural vibration piece is reduced in size by shortening the length of the base portion in the longitudinal direction, and the distance from the vibrating arm to the fixing position of the support arm is increased to suppress vibration leakage.

  In addition, with further downsizing of electronic devices and the like, tuning fork-type bending vibration pieces including a pair of vibrating arms extending from the base and a supporting arm extending from the base along the vibrating arm are known. As a bending vibrator using such a tuning fork type bending vibration piece, there is a tuning fork type bending vibrator disclosed in Patent Document 1. A tuning fork-type bending vibrator disclosed in Patent Literature 1 includes a base, a pair of vibrating arms extending from the base, and a support arm extending from the base along the vibrating arm between the vibrating arms. A groove-shaped first recess is formed over the entire width of the arm in the width direction.

  According to the tuning fork type bending vibrator having such a configuration, the vibration leaking from the vibrating arm can be attenuated by the first recess of the support arm, the propagation of vibration to the support arm can be reduced, the temperature characteristics and Deterioration of the CI value can be prevented.

JP 2011-15101 A

The flexural vibration piece that vibrates in the flexural vibration mode causes vibration leakage from the vibration arm to the support arm through the base, resulting in an increase in CI value and poor vibration characteristics.
Therefore, it is conceivable to reduce the vibration leakage by increasing the shape of the support arm or the base and increasing the distance between the vibration arm and the support arm, but this is contrary to the demand for downsizing the flexural vibration piece.

  In order to reduce vibration leakage with a small mass element while reducing the shape of the support arm or the base, the present applicant has made various studies on the flexural vibration piece provided with a protrusion on the base. As a result, it was found that vibration leakage can be reduced as compared with a conventional vibrating piece having no protrusion at the base.

  In view of the above problems, an object of the present invention is to provide a bending vibration piece, a vibration device, an electronic apparatus, and a moving body that can reduce vibration leakage of a vibrating arm.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1] A base, a first vibrating arm extending from one end of the base, and a second vibration extending from the one end side by side with the first vibrating arm in plan view An arm and a support arm that extends between the first vibrating arm and the second vibrating arm and extends from the one end side of the base, and the first end of the base has the first Of the side surfaces extending in the extending direction of the second vibrating arm from the side intersecting the extension line of the side surface on the supporting arm side of the side surfaces extending in the extending direction of the vibrating arm, Protrusions are provided on both sides within the range up to the intersection with the extension line and bordered by the center line of the support arm along the extending direction of the support arm. Bending vibration piece.
According to the above configuration, the bending vibration piece that supports the pair of vibrating arms with the supporting arm between the one end and the other end of the base portion by the bending vibration of the vibrating arm at the base portion of the gap between the vibrating arm and the supporting arm. Thus, bending deformation that repeats compressive stress or tensile stress occurs. When a weight like a protrusion is formed in this area, the moment changes due to the protrusion and unbalanced and vibration leakage occurs in a state where the left and right vibrating arms flexibly vibrate with the support arm as the center line. It becomes easy. However, if multiple protrusions are formed between the pair of vibrating arms and the other end of the base that overlaps with the base in between, the left and right vibrating arms are flexibly vibrated with the support arm as the center line. In this state, a balanced state can be maintained without changing the moment by the plurality of protrusions, and the occurrence of vibration leakage can be reduced.

Application Example 2 The protrusion is provided within a range from a center line between the first vibrating arm and the support portion to a center line between the second vibrating arm and the support portion. The bending vibration piece according to Application Example 1, wherein the bending vibration piece is provided.
According to the above configuration, in the state where the left and right vibrating arms are flexibly oscillating in a well-balanced manner with the support arm as the center line, a state in which the moment is not changed by the plurality of protrusions is maintained, and vibration leakage is particularly generated. Can be reduced.

Application Example 3 The other end of the base has a reduced width portion in which the length in the width direction gradually decreases in the direction opposite to the extending direction of the support arm, and the protrusion A range satisfying 0% <X / L ≦ 37%, where L is the distance from the center line of the support arm to the other end, and X is the distance from the center line of the support arm to the protrusion. The bending vibration piece according to Application Example 1 or 2, wherein the bending vibration piece is provided inside the bending vibration piece.
According to the above configuration, the vibration transmitted to the base due to the bending vibration of the vibrating arm is attenuated (relaxed / absorbed) by the reduced width portion, so that the vibration energy leaking from the support arm is reduced. In addition, in a state where the left and right vibrating arms are flexibly vibrating in a well-balanced manner with the support arm as the center line, it is possible to maintain a balanced state without changing moments by a plurality of protrusions, and particularly reduce the occurrence of vibration leakage. it can.

Application Example 4 When the distance from the center line of the support arm to the end of the other end is L and the distance from the center line of the support arm to the protrusion is X, the plurality of protrusions is 0%. The bending vibration piece according to Application Example 1 or 2, wherein the bending vibration piece is provided in a range satisfying <X / L ≦ 40%.
According to the above configuration, in the state where the left and right vibrating arms are flexibly oscillating in a well-balanced manner with the support arm as the center line, a state in which the moment is not changed by the plurality of protrusions is maintained, and vibration leakage is particularly generated. Can be reduced.

[Application Example 5] The bending vibration according to any one of Application Examples 1 to 4, wherein the plurality of protrusions are provided at positions symmetrical with respect to the center line of the support arm. Fragment.
According to the above configuration, in a state where the left and right vibrating arms are flexibly oscillating in a well-balanced manner with the support arm as the center line, the moment is changed by a plurality of protrusions arranged in a well-balanced manner around the support arm at the other end of the base. The occurrence of vibration leakage can be particularly reduced by maintaining a balanced state.

Application Example 6 A vibration device including the bending vibration piece according to any one of Application Examples 1 to 5.
According to the above configuration, it is possible to provide a vibration device that reduces vibration leakage and reduces the CI value and has excellent vibration characteristics.

Application Example 7 An electronic apparatus comprising the flexural vibration piece according to any one of Application Examples 1 to 5.
According to the above configuration, since the bending vibration piece that reduces vibration leakage and reduces the decrease in the Q value is used, an electronic device that can stably exhibit desired performance is provided.

[Application Example 8] A moving body comprising the bending vibration piece according to any one of Application Examples 1 to 5.
According to the above configuration, since the flexural vibration piece with reduced vibration leakage and reduced Q value is used, a movable body that can stably exhibit desired performance is provided.

It is a top view of the bending vibration piece of this invention. It is the elements on larger scale of the bending vibration piece of this invention. It is a top view of the bending vibration piece of a modification. It is a graph which shows the relationship between the vibration leakage index | exponent of the bending vibration piece of this invention, and the formation location of protrusion of a base other end.

  Embodiments of a flexural vibration piece (also referred to as a vibration piece), a vibration device, an electronic apparatus, and a moving body according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a plan view of a flexural vibration piece of the present invention. FIG. 2 is a partially enlarged view of the flexural vibration piece of the present invention. As shown in FIG. 1, the flexural vibration piece 10 of the present invention includes a base 20, a pair of vibrating arms 30 extending from one end 22 of the base 20, and a pair of vibrating arms 30. A support arm 40 extending from one end 22 of the base 20 is provided.
In the base portion 20 shown in FIG. 1, the side surface on the back side with respect to the one end 22 is the other end 24, and a protruding projection 50 exists on the other end 24 side. The other end 24 extends in a direction perpendicular to the direction in which the vibrating arm 30 extends. In the present embodiment, the one end 22 is, for example, a linear region existing between the vibrating arm 30 and the support arm 40, and the one end 22 and the other end 24 are parallel to each other with the base body interposed therebetween. Is formed. Such a base 20 is formed to have the same length in the length direction parallel to the extending direction of the vibrating arm 30 and the support arm 40.

  The pair of two resonating arms 30 (first resonating arm and second resonating arm) has a base 32 in which an arm portion 32 extends in parallel from the base end toward the front end and is connected to one end 22 of the base portion 20. Each has an end. Groove portions 34 having, for example, a substantially rectangular shape in plan view are formed on the front and back main surfaces of the vibrating arm 30 as grooves extending in the longitudinal direction.

  The vibrating arm 30 is formed with a hammer head portion 36 as a weight portion at the tip of the arm portion 32 as a widened portion having a width larger than the width along the direction orthogonal to the extending direction of the vibrating arm 30 on a plane. . The hammer head portion 36 has a width wider than the width of the arm portion 32 and is formed in a substantially rectangular shape in plan view, but is not limited to this shape, and faces the tip of the hammer head portion 36. The width may be gradually or stepwise widened. The vibrating arm 30 having the hammer head portion 36 vibrates more than the conventional type even if the length extending from the base portion 20 is shorter than the conventional type for the purpose of downsizing the vibrating piece. By setting the mass on the tip side of the arm 30 to be large, it is possible to suppress bending vibration at a frequency higher than necessary. For example, it is possible to maintain the same vibration regardless of the length of the vibrating arm 30. That is, if the hammer head portion 36 is provided on the vibration arm 30, the number of times the vibration arm 30 bends and deforms per unit time is adjusted by changing the mass of the hammer head portion 36, and a desired bending vibration frequency can be easily obtained. be able to. In addition, in the length of the proximal half of the vibrating arm 30 that is flexibly vibrated, the width of the vibrating arm 30 is predominantly the effect of rigidity against bending deformation, whereas the length of the half of the distal end side of the vibrating arm 30 is large. In this case, since the mass load effect predominates in the width of the vibrating arm 30, the hammer head portion 36 is formed in the region on the tip half side of the vibrating arm 30. It is desirable to include a highly effective tip region. Further, the length of the hammer head portion 36 formed at the tip of the vibrating arm 30 with respect to the entire length of the vibrating arm 30 is set to 30% to 50%. Further, the width of the arm portion 32 is increased so as to compensate for the decrease in the bending vibration frequency due to the hammer head. As a result, the thermoelastic loss is reduced and the Q value is remarkably increased. Further, the length of the hammer head portion 36 is 1.2% or more and smaller than 30%, so that the excitation formed on the arm portion 32 is increased. Since the area of the electrode (described later) can be increased, the CI value is drastically reduced.

  Exciting electrodes (not shown) are formed on the surfaces of the arm portion 32 and the groove portion 34, and the vibrating arm 30 is formed at a predetermined frequency by applying a predetermined driving voltage to the excitation electrode via an electrode pad 44 described later. It bends and vibrates in directions toward or away from each other.

  The support arm 40 is between the pair of vibrating arms 30, and an arm portion 42 extends from the base portion 20 at one end 22 along the extending direction of the vibrating arm 30. The length of the support arm 40 in the extending direction is shorter than the length of the vibrating arm 30 in the extending direction, and the distal end of the support arm 40 is disposed closer to the base 20 than the connection portion between the arm portion 32 and the hammer head portion 36. It is set to be. That is, it is desirable that the support arm 40 does not exist between the two hammer head portions 36, but it is sufficient that the support arm 40 does not reach the narrowest portion between the two hammer head portions 36. A pair of electrode pads 44 are formed on the bottom surface of the support arm 40. The bending vibration piece 10 can be adhered to a mounting surface such as a package using a conductive adhesive, and the pair of vibration arms 30 can be fixedly supported by the central support arm 40. Further, it is desirable that the minimum distance between the support arm 40 and the vibrating arm 30 is longer than the minimum distance between the electrode pad 44 and the hammer head portion 36. By doing so, even if the conductive adhesive formed on the electrode pad 44 is formed larger, the possibility of adhering to the vibrating arm 30 is lower than that of the hammer head portion 36, that is, the loss is larger than that of quartz. Since the possibility that the conductive adhesive adheres to the bending deformation portion of the vibrating arm 30 having a great influence on the vibration characteristics is reduced, no fatal characteristic deterioration is caused.

  Tapered portions 38 and 46 are formed at the connecting positions of the vibrating arm 30 and the support arm 40 and the one end 22 of the base 20, respectively. The arm portion 32 of the vibrating arm 30 and the arm portion 42 of the support arm 40 extend in a substantially straight line so as to be parallel to each other from the proximal end to the distal end. A region where the width of the support arm 40 becomes narrow may be provided. By doing this, the vibration frequency of the mode in which the two vibrating arms 30 both bend and vibrate in the same direction (hereinafter referred to as the in-phase mode) is changed to the mode in which the two vibrating arms 30 alternately repeat the approach and the separation from each other (hereinafter referred to as the following) Main mode) can be separated from the vibration frequency, and the coupling strength between the in-phase mode and the main mode can be reduced, thereby preventing the main mode vibration leakage from increasing. In particular, when the vibration frequency of the common mode is f1 and the vibration frequency of the main mode is f0, | f1-f0 | / f0 ≧ 10%, more preferably | f1-f0 | / f0 ≧ 20%, The coupling between the two can be greatly suppressed. The arm portion 32 of the vibrating arm 30 and the arm portion 42 of the support arm 40 are not bent at a right angle or an acute angle from the distal end to the proximal end at the connection position with the one end 22 of the base portion 20, but the width thereof. Rounded taper portions 38 and 46 may be provided so that the diameter gradually increases. The tapered portions 38 and 46 are formed between both side surfaces of the vibrating arm 30 and the support arm 40 and one end 22 of the base portion 20. By providing the tapered portions 38 and 46, it is possible to avoid the concentration of strain when bending vibration occurs, that is, avoid the concentration of temperature change (temperature rise or temperature drop) accompanying the occurrence of strain, and flow of heat. Therefore, the increase in thermoelastic loss can be suppressed, the strength of the connection position can be increased, and the impact resistance can be improved. Note that the width of the vibrating arm 30 of the present embodiment is a region including the width of the arm portion 32 of the vibrating arm 30 and the width of the tapered portions 38 formed on both side surfaces of the arm portion 32. In addition, the width of the support arm 40 in the present embodiment is a region including the width of the arm portion 42 of the support arm 40 and the width of the tapered portions 46 formed on both side surfaces of the arm portion 42.

The other end 24 of the base 20 is formed with a plurality of protrusions that protrude in the direction opposite to the direction in which the vibrating arm 30 and the support arm 40 extend. The protrusions 50a and 50b of the present embodiment are formed on the other end 24 of the base 20 that is line-symmetric with respect to the support arm 40 as a center line. The protrusions 50a and 50b are provided on the other end side of the base portion 20 from the side intersecting with the extension line of the side surface on the support arm 40 side among the side surfaces extending in the extending direction of the first vibrating arm 30. Of the side surfaces extending in the extending direction of the support arm 40, it is within a range up to a place intersecting the extension line of the side surface on the support arm 40 side, and the center line of the support arm 40 along the extending direction of the support arm 40 is a boundary. It is provided on both sides.
The protrusions 50a and 50b have a protrusion length from the other end 24 of the base portion 20 as an example of about 30 μm, and the resonance frequency is higher than the resonance frequency of the pair of vibrating arms 30 so as not to resonate with the vibrating arms 30. I have to. The widths of the protrusions 50a and 50b are set smaller than the widths of the vibrating arm 30 and the support arm 40.
As shown in FIG. 2, the length from the center line in the extending direction of the support arm 40 to the end of the base 20 is L, the length from the center line of the support arm 40 to the center line of the protrusion 50 is X, It is defined as the distance a between the center lines c that bisect the space between the support arm 40 and the vibrating arm 30 on both sides of the arm 40.

  FIG. 3 is a plan view of a bending vibration piece according to a modification. As shown in the figure, the bending vibration piece 10A of the modification is different from the bending vibration piece 10 shown in FIG. Other configurations are the same as those of the bending vibration piece 10 shown in FIGS. 1 and 2, and the same reference numerals are given and detailed description thereof is omitted. The bending vibration piece 10A of the modified example has a reduced width portion 26 in which the length in the direction in which the vibrating arms 30 are arranged along the protruding direction is gradually reduced at the other end 24A of the base portion 20A. According to the flexural vibration piece 10A of the modified example having such a configuration, the vibration at the base caused by the flexural vibration of the vibrating arm is canceled (relaxed / absorbed) by the reduced width portion 26. Therefore, the support arm connected to the base The vibration of becomes small. Therefore, when the fixing portion to be mounted on the package is provided on the support arm, vibration leakage can be extremely reduced as compared with a bending vibration piece having a base portion without the reduced width portion 26.

  In addition, the bending vibration pieces 10 and 10A of the present embodiment are made of a known photo-etching technique using a piezoelectric material such as crystal, lithium tantalate, lithium niobate, lithium trabate, potassium niobate, potassium phosphate, or langasite. And can be formed into a desired outer shape. As an example, when the crystal axis is made of crystal having an X axis (electric axis), a Y axis (mechanical axis), and a Z axis (optical axis), the Y axis is 0 ° or more and 15 ° or less around the X axis. If the coordinate axis Y′-axis forming the angle is set to the thickness direction in the direction perpendicular to the Y′-axis and the X-axis, the Y′-axis direction is usually oriented in the longitudinal direction of the vibrating arm (hereinafter referred to as crystal Z Called a board).

  The bending vibration pieces 10 and 10A having such a configuration are manufactured by the following process when using quartz as an example. The bending vibration pieces 10 and 10A are manufactured on the basis of a wafer-like base material having a flat plate shape by polishing the surface of a quartz crystal Z plate. A protective film in which a Cr film or a Ni film is formed on the surface of the quartz wafer and an Au film is further laminated on the surface is formed by vapor deposition or sputtering. Then, after applying a resist film on the surface of the protective film, patterning is performed by photolithography to a shape slightly wider than the outer shape of the resist film and the bending vibration pieces 10 and 10A. Next, the protective film is etched away using the patterned resist film as a mask. After peeling off the resist film, the resist film is applied again, and the outer shape and groove shape including the plurality of protrusions 50a and 50b are patterned. In this state, the exposed portion of the quartz wafer is etched with hydrofluoric acid to form the outer shape of the bending vibration pieces 10 and 10A.

  Next, the protective film formed in the groove 34 is etched. The crystal surface thus etched and exposed corresponds to the planar shape of the groove 34 formed in the vibrating arm 30. Then, the exposed portion of the quartz wafer is half-etched with hydrofluoric acid for a predetermined time to form a groove 34 in the vibrating arm 30. After the etching of the groove 34, the resist film and the protective film are peeled off.

  The electrode is formed as follows. As an example, an electrode film made of an Au film formed with a Cr film (or Ni film) as a base is formed on the entire surface of the quartz wafer, and a resist film corresponding to the pattern of the excitation electrode is formed on the electrode film. Then, the excitation film is formed by etching the electrode film. After etching the electrode, the resist film is peeled off.

  Next, a weight is attached to the tip of the vibrating arm 30. In this method, a metal film such as Au is formed as a weight adjusting film for frequency adjustment on a part or the entire surface of the hammer head portion 36 by vapor deposition or sputtering.

In the rough adjustment of the frequency, a part of the weighting film is irradiated with a laser beam or the like to partially evaporate, and the mass of the hammer head portion 36 is adjusted. Thereby, the bending vibration frequency of the plurality of bending vibration pieces 10 formed on the quartz wafer can be roughly adjusted to a desired frequency (for example, 32.768 kHz).
Finally, the bending vibration pieces 10 and 10A are separated. That is, the thin connecting portion in the quartz wafer is broken, and the bending vibration piece in the connected state is made into individual pieces.

FIG. 4 is a graph showing the relationship between the vibration leakage index of the flexural vibration piece of the present invention and the location of the protrusion at the other end of the base. Here, as an example, the shape of the bending vibration piece 10 used for the calculation is 860 μm in total length, 248 μm in length L from the center line in the extending direction of the support arm 40 to the end of the base 20, and the center of the support arm 40. The length from the line to the side of the support arm 40 is 50 μm, and the length from the center line of the support arm 40 to the side of the vibrating arm 30 on the support arm 40 side (the side on the inside of the vibrating piece) is 155 μm. The length from the center line of the arm 40 to the side of the vibrating arm 30 on the end side of the base 20 (side outside the vibrating arm 30) is 207 μm, and the protrusion 50a at the other end of the base 20 from the center line of the support arm 40, The length to the formation location of 50b (the center line in the protruding direction of the protrusions 50a and 50b) is X, the protrusions 50a and 50b are square in plan view, and the length in the protruding direction is 30 μm. The depth of the groove 34 is 45 μm, the width of the hammer head is 198 μm, the length is 237 μm, and the bending vibration frequency is in the vicinity of 32.768 kHz. The following calculation was performed assuming that the bending vibration piece 10 was mounted on a ceramic package with a silicon-based conductive adhesive having a film thickness of 20 μm.
The elastic energy resulting from the bending vibration of the bending vibration piece 10 reaches the conductive adhesive via the support arm 40 and is virtually provided on the back surface of the conductive adhesive (the side opposite to the bending vibration piece 10). The calculation is performed on the condition that the bending vibration piece 10 is not returned while being transmitted to the semi-infinite medium having the material constant of the ceramic package. Since this energy transmitted to the semi-infinite medium does not contribute to bending vibration again in the bending vibration piece 10, it becomes a loss due to vibration leakage. The Q value considering only the loss due to the vibration leakage is defined as QLeak (when the vibration leakage increases, QLeak decreases). Further, as can be easily imagined from the mechanism described later, the present invention does not depend on the absolute value of the dimensions, the bending vibration frequency, or the material described above.

  The vertical axis of the graph is the vibration leakage index (Q0 / QLeak). Here, Q0 is a Q value considering only vibration leakage when the other end 24 of the base 20 is not formed with the protrusions 50a and 50b, and QLeak is two protrusions 50a and 50b on the other end 24 of the base 20. The Q value considering only the vibration leakage when formed is shown. The horizontal axis of the graph is the formation position (X / L) of the protrusions 50a and 50b at the other end 24 of the base 20, and when X / L = 0, the center line of the support arm 40 and the center line of the protrusions 50a and 50b overlap. When X / L = 1, the end of the base 20 and the center line of the protrusions 50a and 50b overlap each other. A straight line A passing through the vibration leakage index 1.0 of the graph and parallel to the vertical axis indicates a case where there is no protrusion at the other end of the base of the bending vibration piece. The ◇ plot is the bending vibration piece 10 shown in FIG. 1 in which the one end 22 and the other end 24 of the base 20 are formed in parallel with the base body interposed therebetween. □ The plot shows the bending vibration piece shown in FIG. 3, in which the other end 24 </ b> A of the base portion 20 </ b> A has a reduced width portion 26 in which the length in the direction in which the vibrating arms 30 are arranged is gradually reduced along the protruding direction. 10A.

  When the vibration leakage index is smaller than 1.0, the vibration leakage is smaller than that of the bending vibration piece in which no protrusion is formed on the other end of the base. In the case of the bending vibration piece 10 shown in FIG. 1, the range of X / L in which the vibration leakage index is smaller than 1.0 is 0 <X / L ≦ 0.37. When this range of X / L is expressed as a percentage, 0% <X / L ≦ 37%. This range is a region at the other end of the base where a plurality of protrusions 50a and 50b overlap between the pair of vibrating arms at one end of the base and the base. Specifically, a region connecting two center lines (c in FIG. 2) formed between each of the pair of vibrating arms 30 at one end of the base and the support arm 40, and the base 20 between This is a case where it is formed in a region (an arrow a in FIG. 2) of the other end 24 of the base portion 20 that overlaps at least between the two.

  The vibrating arm 30 is configured to bend and vibrate in a direction in which the vibrating arms 30 approach or separate from each other at a predetermined frequency by applying a predetermined driving voltage to the excitation electrode. When the pair of vibrating arms 30 are bent and deformed so as to be separated from each other, the support arm 40 is fixed to the package via the electrode pads 44 and the conductive adhesive, and therefore the base 20 is bent and deformed in the extending direction of the vibrating arms 30. However, in particular, the portion of the base 20 located between the base end of the support arm 40 and the base end of the support arm 30 and the base 20 located in the direction opposite to the extending direction of the vibrating arm. This part will be bent greatly. For this reason, when the protrusion 50 is formed in this region, in the state where the left and right vibrating arms 30 are bent and vibrated in a well-balanced manner with the support arm 40 as the center, the balance of deformation and the balance of moment are lost due to the protrusion and unbalanced. Thus, vibration leakage is likely to occur.

  On the other hand, when a plurality of protrusions 50a and 50b on the other end 24 of the base 20 are formed in a region overlapping between the pair of vibrating arms at one end of the base and the base interposed therebetween, In a state where the vibrating arm 30 is flexibly vibrating in a well-balanced manner, a plurality of protrusions arranged in line symmetry with respect to the center line of the support portion maintain a balanced state without changing the moment, and vibration leakage occurs. Can be reduced.

  Next, in the case of the bending vibration piece 10A shown in FIG. 3, the range of X / L where the vibration leakage index is smaller than 1.0 is 0 <X / L ≦ 0.40. When this range of X / L is expressed as a percentage, 0% <X / L ≦ 40%. This range is a region at the other end of the base where a plurality of protrusions 50a and 50b overlap between the pair of vibrating arms at one end of the base and the base. Specifically, a region connecting two center lines (c in FIG. 2) formed between each of the pair of vibrating arms at one end of the base and the support arm, and at least the base interposed therebetween It is a case where it forms in the area | region (arrow a in FIG. 2) of the other end of the said base which overlaps.

  A flexural vibration piece 10A shown in FIG. 3 has a reduced width portion at the other end 24A of the base portion 20A where the width along the direction in which the vibrating arms 30 are arranged gradually decreases toward the center line. In the flexural vibration piece 10A, the rigidity of the connecting portion between the support arm 40 and the base portion 20A is increased, and the flexural vibration of the vibration arm 30 causes the base portion 20A of the gap portion between the vibration arm 30 and the support arm 40 to move to the base portion 20A. Flexural deformation that repeats compressive stress or tensile stress at one end and the other end is unlikely to occur. For this reason, the bending vibration piece 10A shown in FIG. 3 can significantly reduce vibration leakage as compared with the bending vibration piece 10 of FIG. However, in the base portion 20A in the region of the gap between the vibrating arm 30 and the support arm 40, a slight bending deformation that repeats compressive stress or tensile stress occurs at one end and the other end of the base portion 20 due to bending vibration of the vibrating arm 30. Therefore, when a weight such as the protrusion 50 is formed in this region, the moment is changed by the protrusion and becomes unbalanced in a state where the left and right vibrating arms 30 are flexibly oscillating with the support arm 40 as the center. Is likely to occur.

  On the other hand, when a plurality of protrusions 50a and 50b on the other end 24 of the base 20 are formed in a region overlapping between the pair of vibrating arms at one end of the base and the base interposed therebetween, In a state where the vibrating arm 30 is flexibly vibrating in a well-balanced manner, the moment is not changed by a plurality of protrusions arranged in line symmetry with respect to the center line of the support portion, and a balanced state is maintained and vibration leakage is prevented. Generation can be reduced.

  According to such a flexural vibration piece of the present invention, the protrusion at the other end of the base is formed between the pair of vibrating arms at one end of the base and the region overlapping with the base interposed therebetween, In the state where the left and right vibrating arms are flexibly oscillating in a balanced manner, a plurality of protrusions arranged symmetrically with respect to the center line of the support portion maintain a balanced state without changing the moment, and vibration leakage Generation can be reduced. In addition, when the other end 24A of the base 20A has a reduced width portion in which the width along the direction in which the vibrating arms 30 are arranged gradually decreases toward the center line, A balanced state can be maintained without changing moment by a plurality of protrusions arranged in line symmetry, and the occurrence of vibration leakage can be particularly reduced.

  The present invention is not limited to the above embodiments, and can be implemented with various modifications or changes within the technical scope thereof. For example, the pair of two vibrating arms can be applied even when the arm portion is extended substantially linearly from the proximal end to the distal end without forming the hammer head portion at the distal end.

  Further, the flexural vibration piece of the present invention can be mounted on packages having various structures, and can be applied to various vibration devices other than vibrators such as an oscillator combined with a circuit element having an oscillation circuit.

  Further, the bending vibration piece of the present invention is combined with a circuit element having an oscillation circuit, thereby allowing a digital mobile phone, a personal computer (mobile personal computer), an electronic timepiece, a video recorder, a video camera, a television, a digital still camera, and an ink jet. Dispenser (for example, inkjet printer) Laptop personal computer, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, security TV Monitors, electronic binoculars, POS terminals, medical devices (for example, electronic thermometers, blood pressure meters, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), fish detectors, various measuring devices, instruments (for example, vehicles) , Sky machine, gauges of a ship), can be used widely as an electronic device such as a flight simulator.

  Moreover, the bending vibration piece of the present invention is mounted on an automobile. Bending vibration pieces are keyless entry, immobilizer, car navigation system, car air conditioner, anti-lock brake system (ABS), airbag, tire pressure monitoring system (TPMS), engine control, hybrid car and electric The present invention can be widely applied to electronic control units (ECU) such as automobile battery monitors and vehicle body control systems. By combining with a circuit element having an oscillation circuit, it can be widely used as a moving body such as a GPS (global positioning system).

10, 10A ......... Bending vibration piece, 20, 20A ......... Base, 22, 22A ......... One end, 24, 24A ......... Other end, 26 ......... Reduced width portion, 30 ......... Vibrating arm, 32... Arm portion 34... Groove portion 36... Hammer head portion 40... Support arm 42 42 Arm portion 44 Electrode pads 50 a and 50 b Projection

Claims (8)

The base,
A first vibrating arm extending from one end side of the base, and a second vibrating arm aligned with the first vibrating arm in plan view and extending from the one end side;
A support arm between the first vibrating arm and the second vibrating arm and extending from the one end side of the base,
With
The other end side of the base part extends in the extending direction of the second vibrating arm from a position intersecting with the extension line of the side surface on the supporting arm side among the side surfaces extending in the extending direction of the first vibrating arm. Out of the expanding side surfaces, it is within a range up to a place intersecting with the extension line of the side surface on the support arm side, and on both sides with the center line of the support arm extending in the extending direction of the support arm as a boundary A bending vibration piece characterized in that a protrusion is provided.   The protrusion is provided in a range from a center line between the first vibrating arm and the support portion to a center line between the second vibrating arm and the support portion. The bending vibration piece according to claim 1. The other end of the base portion has a reduced width portion whose length in the width direction gradually decreases as it goes in a direction opposite to the extending direction of the support arm,
The protrusion has a distance from the center line of the support arm to the end of the other end as L, and a distance from the center line of the support arm to the protrusion as X.
The bending vibration piece according to claim 1, wherein the bending vibration piece is provided in a range satisfying 0% <X / L ≦ 37%. When the distance from the center line of the support arm to the other end is L and the distance from the center line of the support arm to the protrusion is X, the plurality of protrusions,
The bending vibration piece according to claim 1, wherein the bending vibration piece is provided within a range satisfying 0% <X / L ≦ 40%.   5. The flexural vibration piece according to claim 1, wherein the plurality of protrusions are provided at positions symmetrical with respect to the center line of the support arm.   A vibration device comprising the bending vibration piece according to claim 1.   An electronic apparatus comprising the bending vibration piece according to claim 1.   A moving body comprising the bending vibration piece according to claim 1.

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