JP3978783B2 - Piezoelectric device, mobile phone device using piezoelectric device, and electronic equipment using piezoelectric device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a piezoelectric device and a cellular phone and an electronic apparatus using the improved piezoelectric device.
[0002]
[Prior art]
Piezoelectric vibrating piece housed in a package for small information devices such as HDDs (hard disk drives), mobile computers, IC cards, and mobile communication devices such as mobile phones, car phones, and paging systems Piezoelectric devices such as vibrators and piezoelectric oscillators are widely used.
FIG. 7 is a schematic cross-sectional view showing a configuration example of such a piezoelectric device (see Patent Document 1).
In the figure, a piezoelectric device 1 contains a piezoelectric vibrating piece 3 inside a package 2. In this case, the package 2 is formed by forming an insulating material in a shallow box shape, and after the piezoelectric vibrating reed 3 is accommodated and fixed inside, the package 2 is sealed by the lid 4.
[0003]
The package 2 is formed by molding, laminating and sintering a plurality of substrates 2a, 2b, 2c made of ceramic green sheets, and is formed inside the substrate 2c by removing the material during molding. By providing the hole, a space S1 for accommodating the piezoelectric vibrating piece 3 is formed as shown in the figure.
[0004]
The piezoelectric vibrating piece 3 is formed of a so-called tuning fork type vibrating piece having a pair of vibrating arms extending in parallel from the base to one side by etching a quartz crystal, for example. An excitation electrode for the electrode is formed.
The piezoelectric vibrating reed 3 is supported in a cantilevered manner by joining the base 3a at the internal space S1 of the package 2 to the package side.
[0005]
Specifically, an electrode portion 5 connected to a mounting electrode portion (not shown) provided on the bottom surface of the package is formed on the surface of the substrate 2a of the package 2, and the base portion of the electrode portion 5 and the piezoelectric vibrating piece 3 is formed. 3 a is joined by the conductive adhesive 6.
Further, in this piezoelectric device 1, a recess 7 is provided in the region immediately below the tip 3 b of the piezoelectric vibrating piece 3 inside the package 2 by removing the material in the corresponding region of the substrate 2 b. Thereby, when the piezoelectric device 1 receives an impact in the Z direction from the outside, the tip portion 3b of the piezoelectric vibrating piece 3 is shaken in the direction of the arrow D to avoid being damaged by colliding with the inner bottom surface of the package 2. Have been to.
[0006]
[Patent Document 1]
JP 2002-359535 A
[0007]
[Problems to be solved by the invention]
Incidentally, the piezoelectric device 1 configured as described above has several problems. That is, since the piezoelectric vibrating reed 3 is joined at the base 3a, which is one end thereof, and is supported in a cantilevered manner, the tip 3b of the piezoelectric vibrating reed 3 when subjected to an impact in the Z direction from the outside. The amount of displacement in the Z direction is large. For this reason, since it is necessary to provide the recess 7 in the package 2 in order to prevent damage to the tip 3b of the piezoelectric vibrating reed 3 at the time of impact, there is a restriction in reducing the overall size h of the package 2 in the thickness direction. This is disadvantageous in reducing the product height.
In particular, when the piezoelectric vibrating piece 3 has a cantilever support structure using the conductive adhesive 6, the piezoelectric vibration is caused by contraction of the conductive adhesive 6 in the process of curing the conductive adhesive 6 during the bonding. In some cases, the tip 3b of the piece 3 is inclined and fixed so as to face downward, and from this point, the necessity of providing the above-described recess 7 becomes higher.
[0008]
In addition, since the distance between the base portion 3a, which is a joint portion between the piezoelectric vibrating piece 3 and the package 2, and the tip portion 3b of the piezoelectric vibrating piece 3, the bending moment increases upon impact from the outside of the piezoelectric device 1. The damage to the joint structure at the base 3a is large.
[0009]
Further, since the base portion 3a which is a joint portion with respect to the package 2 is close to the excited vibration portion, vibration easily leaks from the vibration side of the piezoelectric vibrating piece 3 to the base portion 3a, and the vibration propagates to the package 2 side. As a result, the oscillation performance is adversely affected.
[0010]
The present invention has been made to solve the above-described problems, and is advantageous for reducing the height of the piezoelectric device, and is less likely to be damaged because the burden on the joining portion of the piezoelectric vibrating piece is small during an external impact. An object of the present invention is to provide a piezoelectric device that hardly changes in oscillation frequency, and a mobile phone and an electronic apparatus using the piezoelectric device.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a piezoelectric device in which a tuning-fork type crystal vibrating piece is joined in a package at least at one position in the length direction, and the package is sealed with a lid. The package includes a substrate constituting a bottom portion of the package and an electrode portion formed on the substrate, and the tuning fork type crystal vibrating piece includes a base and a plurality of vibrations extending in parallel from the base. An arm, and a plurality of fixing arms extending in parallel with the vibrating arm from the base, and each of the fixing arms, The center of gravity of the tuning-fork type quartz vibrating piece Position near only By being joined to the electrode part through a conductive adhesive, an impact from outside acts, Tuning fork type The base of the crystal vibrating piece and the tip of the vibrating arm are Z-axis direction This is achieved by a piezoelectric device that is configured to be displaced in the distance.
According to the configuration of the first invention, the piezoelectric vibrating piece accommodated in the package is bonded to the fixing arm different from the vibrating arm at a location near the center of gravity of the piezoelectric vibrating piece. The bending moment of the vibrating arm can be distributed to both sides of the joint portion as compared with the cantilever type support structure joined at the end as in the prior art.
For this reason, the amount of displacement of the tip of the vibrating arm can be reduced in the event of an impact from the outside, and it is possible to effectively prevent a collision and damage to the inside of the package. Further, since the vibration arm and the joint portion are separated from each other, leakage of vibration from the vibration arm to the package side through the joint portion can be reduced. Furthermore, since the bending moment that acts on the joint portion in the event of an external impact can be reduced, it is possible to effectively prevent the joint portion between the package and the piezoelectric vibrating piece from being damaged.
[0013]
The second invention is the configuration of the first invention, The plurality of fixing arms are a pair of arms having the same length arranged on both outer sides of the plurality of vibrating arms.
According to the configuration of the second invention, The pair of arms have the same form as each other and have a symmetric structure with respect to a virtual center line passing through the center in the width direction. It is strengthened and can be fixed in a balanced manner.
[0014]
A third invention is the configuration of the second invention, The plurality of fixing arms are formed shorter than the plurality of vibrating arms.
According to the configuration of the third invention, The fixing arm used for joining does not cause an extremely large weight increase, and the size in the length direction does not need to be increased.
[0015]
According to a fourth invention, in any one of the first to third inventions, The plurality of vibrating arms and the fixing arm extend in the same direction from the base, and further include a balance portion extending from the base in a direction opposite to the one direction.
According to the configuration of the fourth invention, By providing the balance portion that extends in a direction opposite to the direction in which the vibrating arm extends, the joint position in the vicinity of the center of gravity moves to the base side, making it easier to balance the stress distribution. Further, the piezoelectric vibrating piece having a shorter vibrating arm can be fixed at an appropriate position. That is, in the piezoelectric vibrating reed having a short vibrating arm, if there is no balance portion, the center of gravity is shifted toward the distal end portion, and therefore, a suitable balance can be obtained by bringing the center of gravity closer to the base portion.
[0016]
A fifth invention is the configuration of the fourth invention, The balance portion includes a narrow neck portion integrally coupled to the base portion, and a head portion widened on the tip side from the neck portion.
According to the configuration of the fifth invention, By creating a portion that is easily deformed by providing the neck portion, the balance portion is easily deformed symmetrically with the bending deformation of the vibrating arm across the joining portion, and an impact from the outside is further increased. By appropriately dispersing, the amount of displacement can be further reduced.
[0017]
According to a sixth invention, in any one of the first to fifth inventions, The fixing arm of the piezoelectric vibrating piece is bonded to an electrode portion provided on an inner bottom surface of the package by a metal bump.
According to the configuration of the sixth invention, By joining the piezoelectric vibrating reeds using metal bumps, a joining structure for holding the piezoelectric vibrating reeds horizontally can be realized, and the conduction performance can be ensured.
[0018]
In addition, according to the seventh aspect of the present invention, the tuning fork type quartz crystal vibrating piece is bonded to the package at least at one position in the length direction, and the package is sealed with a lid. A mobile phone device using a piezoelectric device, wherein the package includes a substrate constituting a bottom portion of the package, and an electrode portion formed on the substrate, and the tuning-fork type crystal vibrating piece includes a base, A plurality of vibrating arms extending in parallel from the base, and a plurality of fixing arms extending in parallel with the vibrating arm from the base, each of the fixing arms, The center of gravity of the tuning-fork type quartz vibrating piece Position near only By being joined to the electrode part through a conductive adhesive, an impact from outside acts, Tuning fork type The base of the crystal vibrating piece and the tip of the vibrating arm are Z-axis direction This is achieved by a mobile phone device in which a clock signal for control is obtained by a piezoelectric device that is configured to be displaced in the direction.
[0019]
According to the eighth aspect of the present invention, the tuning fork type quartz crystal vibrating piece is joined to the package at least at one position in the length direction, and the package is sealed with a lid. An electronic apparatus using a piezoelectric device, wherein the package includes a substrate constituting a bottom portion of the package and an electrode portion formed on the substrate, and the tuning-fork type crystal vibrating piece includes a base, and the base A plurality of vibrating arms extending in parallel from the base, and a plurality of fixing arms extending in parallel with the vibrating arm from the base, each of the fixing arms, The center of gravity of the tuning-fork type quartz vibrating piece Position near only By being joined to the electrode part through a conductive adhesive, an impact from outside acts, Tuning fork type The base of the crystal vibrating piece and the tip of the vibrating arm are Z-axis direction This is achieved by an electronic apparatus in which a control clock signal is obtained by a piezoelectric device configured to be displaced in the direction.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an embodiment of a piezoelectric device of the present invention. FIG. 1 is a schematic plan view thereof, and FIG. 2 is a schematic cross-sectional view taken along line AA of FIG.
In the figure, the piezoelectric device 30 shows an example in which a piezoelectric vibrator is configured, and the piezoelectric device 30 houses a piezoelectric vibrating piece 32 in a package 36 which is a base. The package 36 is open at the top and is sealed by a lid 39. At least a part of the package 36 is formed by, for example, laminating a plurality of substrates formed by molding an aluminum oxide ceramic green sheet as an insulating material, and then sintering.
[0021]
That is, in this embodiment, the package 36 is formed by sequentially laminating the first substrate 61 and the second substrate 62, and the material inside the second substrate 62 is removed, so that the internal space S2 is removed. A space is formed. This internal space S2 is a housing space for housing the piezoelectric vibrating piece.
In this embodiment, the box-shaped package 36 is formed to accommodate the piezoelectric vibrating piece 32. For example, the first substrate 61 is used as a base, and the piezoelectric vibrating piece 32 is bonded thereto. In addition, a package (accommodating container) configured to be covered with a thin box-shaped lid or lid body and sealed may be used.
[0022]
1 and 2, in the vicinity of the end portion in the internal space S2 of the package 36 as a base, the first substrate 61 that is exposed to the internal space S2 and forms the inner bottom portion is formed of, for example, nickel on tungsten metallization. Electrode portions 31, 31 formed by plating and gold plating are provided.
In this embodiment, the electrode portions 31 are provided near both ends in the width direction of the first substrate 61 and near the center in the length direction.
The electrode portions 31 are connected to the outside to supply a driving voltage. Specifically, for example, a mounting electrode part (not shown) is formed on the bottom surface of the first substrate 61, and the mounting electrode part and the electrode parts 31, 31 are tungsten metallized before firing the first substrate 61. Etc. can be connected by a conductive through-hole formed using the like.
[0023]
Metal bumps 43, 43 are disposed in advance on the electrode portions 31, 31, and the piezoelectric vibrating piece 32 is joined from above. For example, gold bumps are used as the metal bumps 43. 1 and 2, the size of the metal bump 43 is shown larger than the actual size in order to clarify the bonding position.
Here, as a method of forming such metal bumps 43, 43, a plating method or a stud bump forming method is used. That is, in the plating method, gold or a gold alloy as a metal material for forming a metal bump is formed on the electrode portion 31 and then reflowed to form a hemispherical bump. Or you may form by vapor deposition or paste printing.
[0024]
Further, not only the plating method but also ball bumps or stud bumps may be used. That is, a ball is formed by heating and melting a gold wire at the tip exposed from the capillary with an electric torch or a hydrogen torch. Then, it can be formed by being moved onto the electrode part 31 and ultrasonically pressure-bonding with heat.
The piezoelectric vibrating piece 32 is bonded by pressing a fixing arm, which will be described later, to the metal bumps 43, 43, or by applying heat, pressure, or ultrasonic pressure combined use.
[0025]
The piezoelectric vibrating piece 32 is formed of, for example, quartz, and a piezoelectric material such as lithium tantalate or lithium niobate can be used in addition to quartz.
The piezoelectric vibrating piece 32 includes a base 51 and a pair of vibrating arms 34 and 35 extending from the base 51 in parallel to the left in FIG. In addition, the base 51 has a strip-like shape that expands in the width direction that is the X direction, and is provided one by one on each outer side of the pair of vibrating arms 34 and 35 described above, and in the same direction as the pair of vibrating arms 34 and 35. Are provided with a pair of fixing arms 37 and 38 extending in parallel with each other.
In other words, the pair of vibrating arms 34 and 35 and the fixing arms 37 and 38 are integrally formed so as to extend in the same direction as the Y direction from the base 51 with the base 51 as a base end. The fixing arms 37 and 38 have the same length and are shorter than the vibrating arms 34 and 35.
Thereby, the piezoelectric vibrating piece 32 has a symmetrical shape with respect to a virtual center line C extending in the length direction of the piezoelectric device 30 of FIG.
[0026]
In FIG. 1, a balance portion 42 is integrally formed on the side opposite to the side on which the vibrating arms 34 and 35 and the fixing arms 37 and 38 are formed with the base 51 interposed therebetween. The balance part 42 is provided in order to balance the behavior related to the displacement of both end portions in the length direction across the joining portion of the piezoelectric vibrating piece 32. The balance portion 42 is located on the right side in FIG. 1 from the base portion 51, and is formed by reducing the width dimension, and a neck portion 54 that is a notch portion or a recess portion, and on the tip side of the neck portion 54. And a head portion 46 formed by enlarging the width dimension.
[0027]
Excitation electrodes 44 and 45 are formed on at least the vibrating arms 34 and 35 of the piezoelectric vibrating piece 32. The excitation electrodes 44 and 45 are formed, for example, by plating chromium as a base and plating gold thereon. The excitation electrodes 44 and 45 are polarized so as to have different polarities, and the excitation electrode 44 has main surfaces (front and back surfaces) and both side surfaces on the distal end side of the vibrating arm 34, and main ends on the proximal end side of the vibrating arm 35. The surface and the base 51 are wound around and are drawn around the main surface of the fixing arm 37. A portion extended by the excitation electrode 44 and routed to the main surface of the fixing arm 37 is a lead-out electrode 44a. The excitation electrode 45 wraps around the main surface (front and back surfaces) and both side surfaces on the distal end side of the vibrating arm 35, the main surface on the proximal end side of the vibrating arm 34, and the base portion 51, and reaches the main surface of the fixing arm 38. Has been routed to. A portion where the excitation electrode 45 is extended and drawn around the main surface of the fixing arm 38 is a lead-out electrode 45a.
[0028]
In addition, at the crotch portion 53 between the vibrating arm 34 and the vibrating arm 35, the excitation electrode 44 and the excitation electrode 45 on the inner side surface of each vibrating arm 34 and the vibrating arm 35 are separated. The lead-out electrodes 44a and 45a drawn around the fixing arms 37 and 38 function as bonding electrodes.
As a result, a drive voltage is applied to the excitation electrodes 44 and 45 from the outside via the electrode portions 31 and 31 of the package 36, whereby an electric field is appropriately formed in each of the vibrating arms 34 and 35. , 35 are driven so as to approach and separate from each other and vibrate at a predetermined frequency.
[0029]
A lid 39 is joined to the open upper end of the package 36 through a brazing material 48 such as low-melting glass to seal the package 36. The lid 39 can be formed of a metal such as Kovar, or can be formed of a transparent glass material. In the case of selecting a transparent material, after sealing and fixing to the package 36, as shown in FIG. 2, a laser beam LB is externally applied to a part of the metal coating portion of the piezoelectric vibrating piece 32 or an excitation electrode (not shown). The frequency adjustment can be performed by a mass reduction method. In this case, the lid 39 is made of, for example, a material that transmits light, particularly, thin glass.
As a glass material suitable for the lid 39, for example, borosilicate glass is used, for example, as a thin glass manufactured by the downdraw method.
[0030]
Next, the bonding structure of the piezoelectric vibrating piece 32 will be described.
The piezoelectric vibrating reed 32 does not have a conventional cantilever support structure, but is obtained by joining the fixing arms 37 and 38 to the electrode portions 31 and 31 on the package 36 side as shown in FIGS. Bonded and fixed.
Specifically, on the inner bottom surface of the package 36 in FIG. 1, the electrode portions 31, 31 are ideally wide from the center of gravity GP of the piezoelectric vibrating piece 32 when the bonded piezoelectric vibrating piece 32 is positioned. It is formed on a virtual straight line GP1 extending in the X direction, which is the direction, and the above-described metal bumps 43 and 43 are provided on the virtual straight line GP1 to be joined to the fixing arms 37 and 38 of the piezoelectric vibrating piece 32. .
[0031]
Alternatively, the joining location may be set by joining the center location of the total length L1 of the piezoelectric vibrating piece 32 as the center of gravity approximate location corresponding to the center of gravity position.
In addition, this joining location can be set and joined as a center of gravity approximate location corresponding to the center of gravity position corresponding to the center of gravity position of the total length L2 of each vibrating arm 34, 35 of the piezoelectric vibrating piece 32. The center portion of the full length L3 of the fixing arms 37 and 38 of the vibrating piece 32 can be set and joined as a center of gravity approximate location corresponding to the center of gravity position. In this case, in order to disperse the balance of the Z-axis displacement symmetrically, the dimensions of the balance portion 42 are adjusted.
The bonding means is not limited to the metal bumps, and a conductive adhesive may be used when the piezoelectric vibrating reed 32 allows a certain change in posture from the horizontal state in the bonded state. In this case, unlike the conventional case, the piezoelectric vibrating piece 32 of the present embodiment does not have a cantilevered support structure. There is no approach to the bottom.
[0032]
The present embodiment is configured as described above, and the piezoelectric vibrating piece 32 housed in the package 36 is in the vicinity of the center of gravity of the piezoelectric vibrating piece 32 with respect to the fixing arms 37 and 38 different from the vibrating arms 34 and 35. It is made to join in the place of. For this reason, the joint location is located in the vicinity of the center of gravity GP of the piezoelectric vibrating piece 32, and the bending moment of the vibrating arm is less than that of the cantilevered support structure joined at the end as in the prior art. Can be distributed on both sides.
That is, when an impact is applied to the piezoelectric device 30 from the outside, both ends E1 and E2 of the piezoelectric vibrating piece 32 shown in FIG. 2 are indicated by arrows with the joint B at the middle position as the center. In addition, they are displaced symmetrically in the Z direction. Thus, by dispersing the impact, the displacement amount of both end portions E1 and E2 of the piezoelectric vibrating piece 32 can be made smaller than the displacement amount of the tip portion of the conventional cantilevered piezoelectric vibrating piece, and the package It can be effectively prevented from colliding with and breaking inside.
[0033]
Furthermore, due to the displacement of both ends E1 and E2, the bending moment to the joint by the metal bump 43 is smaller than the bending moment to the joint B by cantilever support, so the stress applied to the joint B is reduced, It becomes hard to break by that much. For this reason, the reliability of the piezoelectric device 30 is improved.
Further, since the vibration arms 34 and 35 and the joint B are separated from each other, leakage of vibration from the vibration arms 34 and 35 to the package side via the joint can be reduced, and the oscillation frequency is changed. And increase in CI (crystal impedance) value can be effectively suppressed.
[0034]
FIGS. 3 and 4 are views showing SA1 corresponding to the piezoelectric device 1 described in FIG. 7 and SA2 corresponding to the piezoelectric device 30 of the present embodiment.
Among these, FIG. 3 shows a comparison line comparing the amount of displacement of the tip when subjected to an impact from the outside. In the figure, a comparison line T1 shows a case where SA1 and SA2 are joined by a conductive adhesive using a silver paste, and a comparison line T2 shows a case where SA1 and SA2 are joined by metal bumps. FIG. 4 is a diagram comparing the amount of change in oscillation frequency due to vibration leakage. Comparison line T3 shows a case where SA1 and SA2 are joined by a conductive adhesive using silver paste, and comparison line T4 is SA1 and SA2 are shown as being joined by metal bumps.
[0035]
FIG. 3 shows the results of testing with the impact condition set to 43000 G (equivalent to an impact obtained by freely dropping a 100-gram object from a height of 1500 mm). As shown in FIG. 3, at T1 when the joint B in FIG. 2 is joined by a conductive adhesive instead of the metal bump 43, the displacement amount of the tip of the vibrating arm of the piezoelectric vibrating piece is SA1 (conventional structure). And SA2 (this embodiment) show a large difference, indicating the high impact relaxation performance of this embodiment. Moreover, in the joining by metal bump, although a big difference is not seen, the result that this embodiment is more advantageous was obtained.
In FIG. 4, the result that the change of the oscillation frequency was remarkably suppressed was obtained both in the case of joining with the metal bump and the case of joining with the conductive adhesive.
[0036]
FIG. 5 is a schematic plan view showing a relationship between a modified example of the piezoelectric vibrating piece 32 and a place where the piezoelectric vibrating piece 32 is joined to the package, and FIG. 5A is a view showing the piezoelectric vibrating piece 32 described in FIGS. 5 (b) shows a state in which the piezoelectric vibrating piece 32-1 having no balance portion 42 is joined to the package at the position of the virtual line GP1, and FIG. 5 (c) shows the above-described virtual line GP1. A state is shown in which the piezoelectric vibrating piece 32-1 is joined to the package at a location corresponding to the center of gravity position GP2 of the piezoelectric vibrating piece 32-1 different from the virtual line GP1.
[0037]
For each of these forms, when an impact is applied from the outside of the piezoelectric device (the conditions are the same as those in FIG. 3), when the amount of displacement of the tip is examined, first, the amount of displacement shown in FIG. M1 is about 0.5 mm. On the other hand, in the configuration of FIG. 5A, the displacement shown by M2 in FIG. 2 is about 0.18 mm, and in the configuration of FIG. 5B, the displacement is about 0.23 mm. Even in the configuration of c), the displacement was about 0.23 mm.
[0038]
From these results, the piezoelectric vibrating reed 32 of FIG. 5A is provided with the balance portion 42 at the end opposite to the side on which the vibrating arms 34 and 35 of the base 51 are provided, in addition to the base 51. Therefore, the amount of displacement at the tip of each vibrating arm 34, 35 is the smallest and the most advantageous. In particular, the balance portion 42 has a structure in which a head portion 46 having a relatively large mass is integrally joined by a narrowed neck portion 54. That is, in FIG. 5A, with respect to the central axis 51 -L that bisects the length direction of the base 51, the root or base portion of the neck portion 54 that is integrally fixed to the base 51 and the vibrating arms 34 and 35. In addition, the bases or base portions of the fixing arms 37 and 38 are arranged symmetrically.
Therefore, structurally, the base or base portion of the neck portion 54 is easily displaced, and the bases or base portions of the fixing arms 37 and 38 are easily deformed. Are distributed in a balanced manner at the left and right ends with the joint B as the center, with the result that the displacement amount M2 is reduced.
[0039]
Further, even in the configuration in which the balance portion 42 is omitted as in the piezoelectric vibrating piece 32-1 in FIGS. 5B and 5C, the displacement amount M2 is sufficiently small as compared with the conventional case, and FIG. ) And the case of FIG. 5 (c), even if the joining position is slightly changed, substantially the same result can be obtained if the joining is performed at a position substantially corresponding to the position of the center of gravity.
[0040]
FIG. 6 is a diagram showing a schematic configuration of a digital mobile phone device 300 as an example of an electronic apparatus using the piezoelectric device according to the above-described embodiment of the present invention.
In the figure, a microphone 308 for receiving the voice of the sender and a speaker 309 for outputting the received content as a voice output are provided, and further, an integrated circuit or the like as a control unit connected to the modulation and demodulation unit of the transmission / reception signal. CPU (Central
Processing Unit 301 is provided.
In addition to modulation and demodulation of transmission / reception signals, the CPU 301 controls an information input / output unit 302 including an LCD as an image display unit, an operation key for inputting information, and an information storage unit 303 including a RAM and a ROM. To do. For this reason, the piezoelectric device 30 is attached to the CPU 301, and its output frequency is used as a clock signal suitable for the control content by a predetermined frequency dividing circuit (not shown) incorporated in the CPU 301. ing. The piezoelectric device 30 attached to the CPU 301 may not be a single piezoelectric device 30 but may be an oscillator that combines the piezoelectric device 30 and the like with a predetermined frequency dividing circuit and the like.
[0041]
The CPU 301 is further connected to a temperature compensated crystal oscillator (TCXO) 305, and the temperature compensated crystal oscillator 305 is connected to the transmitter 307 and the receiver 306. Thus, even if the basic clock from the CPU 301 fluctuates when the environmental temperature changes, it is corrected by the temperature compensated crystal oscillator 305 and supplied to the transmission unit 307 and the reception unit 306.
[0042]
In this way, by using the piezoelectric device 30 according to the above-described embodiment in an electronic device such as the digital cellular phone device 300 including the control unit, a reduction in the height is realized, and the overall size of the device is reduced. Since the joining structure of the piezoelectric vibrating reed does not adversely affect the vibration performance, an accurate clock signal can be generated.
[0043]
The present invention is not limited to the above-described embodiment. Each configuration of each embodiment can be appropriately combined or omitted, and can be combined with other configurations not shown.
In addition, the present invention is not limited to the name of a piezoelectric vibrator, a piezoelectric oscillator, a gyro sensor, etc., as long as it is covered with a package or a box-shaped lid and accommodates a piezoelectric vibrating piece inside. It can be applied to the piezoelectric device.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an embodiment of a piezoelectric device of the present invention.
FIG. 2 is a schematic cross-sectional view taken along line AA in FIG.
FIG. 3 is a graph comparing displacement amounts of tip portions of vibrating arms of the piezoelectric device of FIG. 1 and a conventional piezoelectric device.
FIG. 4 is a graph comparing changes in vibration performance between the piezoelectric device of FIG. 1 and a conventional piezoelectric device.
FIG. 5 is a schematic plan view showing the relationship between the piezoelectric device of FIG.
FIG. 6 is a diagram showing a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using a piezoelectric device according to an embodiment of the present invention.
FIG. 7 is a schematic cross-sectional view showing an example of a conventional piezoelectric device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 30 ... Piezoelectric device, 31 ... Electrode part, 32 ... Piezoelectric vibration piece, 34, 35 ... Vibrating arm, 37, 38 ... Fixing arm, 42 ... Balance part.

Claims (8)

A piezoelectric device in which a tuning fork type crystal vibrating piece is joined in a package at least at one position in the length direction, and the package is sealed with a lid,
The package is
A substrate constituting the bottom of the package;
An electrode portion formed on the substrate,
The tuning fork type crystal vibrating piece is
The base,
A plurality of vibrating arms extending in parallel from the base;
A plurality of fixing arms extending in parallel with the vibrating arm from the base,
Each of the fixing arms is joined to the electrode portion via a conductive adhesive only at a position near the center of gravity of the tuning-fork type crystal vibrating piece, whereby an impact from the outside acts on the tuning-fork. A piezoelectric device, wherein the base part of the quartz crystal vibrating piece and the tip part of the vibrating arm are displaced in the Z-axis direction .   2. The piezoelectric device according to claim 1, wherein the plurality of fixing arms are a pair of arms having the same length disposed on both outer sides of the plurality of vibrating arms.   The piezoelectric device according to claim 2, wherein the plurality of fixing arms are formed shorter than the plurality of vibrating arms.   The plurality of vibrating arms and the fixing arm extend from the base in the same direction, and further include a balance portion extending from the base in a direction opposite to the one direction. Item 4. The piezoelectric device according to any one of Items 1 to 3.   The said balance part is equipped with the narrow neck part integrally couple | bonded with respect to the said base part, and the head part widened by the front end side from this neck part, The Claim 4 characterized by the above-mentioned. Piezoelectric device.   6. The fixing arm of the tuning-fork type crystal vibrating piece is bonded to an electrode portion provided on an inner bottom surface of the package by a metal bump. Piezoelectric device. A mobile phone device using a piezoelectric device in which a tuning fork type crystal vibrating piece is bonded in a package at least at one position in the length direction and the package is sealed with a lid,
The package is
A substrate constituting the bottom of the package;
An electrode portion formed on the substrate,
The tuning fork type crystal vibrating piece is
The base,
A plurality of vibrating arms extending in parallel from the base;
A plurality of fixing arms extending in parallel with the vibrating arm from the base,
Each of the fixing arms is joined to the electrode portion via a conductive adhesive only at a position near the center of gravity of the tuning-fork type crystal vibrating piece, whereby an impact from the outside acts on the tuning-fork. A mobile phone device characterized in that a control clock signal is obtained by a piezoelectric device in which the base portion of the quartz crystal vibrating piece and the tip portion of the vibrating arm are displaced in the Z-axis direction . An electronic device using a piezoelectric device in which a tuning fork type crystal vibrating piece is joined in a package at least at one position in the length direction, and the package is sealed with a lid.
The package is
A substrate constituting the bottom of the package;
An electrode portion formed on the substrate,
The tuning fork type crystal vibrating piece is
The base,
A plurality of vibrating arms extending in parallel from the base;
A plurality of fixing arms extending in parallel with the vibrating arm from the base,
Each of the fixing arms is joined to the electrode portion via a conductive adhesive only at a position near the center of gravity of the tuning-fork type crystal vibrating piece, whereby an impact from the outside acts on the tuning-fork. An electronic apparatus, wherein a control clock signal is obtained by a piezoelectric device configured such that the base portion of the quartz crystal vibrating piece and the distal end portion of the vibrating arm are displaced in the Z-axis direction .

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