JP7053118B2 - Piezoelectric vibrating pieces, piezoelectric vibrators, oscillators, electronic devices and radio clocks - Google Patents

Description

The present application relates to piezoelectric vibrating pieces, piezoelectric vibrators, oscillators, electronic devices and radio clocks.

As a piezoelectric vibrating piece, a piezoelectric vibrating piece having a structure including a base formed of a piezoelectric material, a pair of vibrating arms extending in a predetermined direction from the base, and a pair of supporting arms extending in a predetermined direction from the base on the outside of the vibrating arm. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-39226

When the pair of vibrating arms of the piezoelectric vibrating piece vibrates, the supporting arms also vibrate due to this vibration. Such vibration leakage from the vibrating arm portion to the supporting arm portion (sometimes referred to as “acoustic leak”) may affect the vibration identification of the piezoelectric vibrating piece.

The purpose of the present application is to suppress vibration leakage from the vibrating arm portion to the supporting arm portion.

In the first aspect, the base portion, the pair of vibrating arms extending from the base portion in the first direction, and the pair of vibrating arms extending in the first direction from the base portion on both outer sides in the arrangement direction of the pair of vibrating arms portions. A pair of supporting arms extending from the base in at least one of the first direction and the opposite direction between the pair of supporting arms and the pair of vibrating arms and the pair of supporting arms. With a part.

By applying a voltage to the piezoelectric vibrating piece made of the piezoelectric material, a pair of vibrating arms extending from the base vibrates at a predetermined frequency. The piezoelectric vibrating piece has a pair of support arms, which are supported by, for example, the support of the package.

Further, the piezoelectric vibrating piece has a pair of intermediate arms. Each of the pair of intermediate arms extends from the base in at least one of the first direction and vice versa between each of the pair of vibrating arms and each of the pair of supporting arms. .. The vibration of the vibrating arm part tries to be transmitted to the support arm part via the base part, but the intermediate arm part extends from the middle of the vibration transmission path. Since a part of the vibration of the vibrating arm is absorbed as the vibration of the intermediate arm, it is possible to suppress the vibration leakage from the vibrating arm to the supporting arm. This makes it possible to improve the vibration characteristics of the piezoelectric vibration piece.

In the second aspect, in the first aspect, the position of the extending tip of the intermediate arm portion in the first direction is the same as the position of the extending tip of the pair of supporting arms.

In the third aspect, in the first aspect, the position of the extending tip of the intermediate arm portion in the first direction or the opposite direction is different from the position of the extending tip of the pair of supporting arms. There is.

As described above, the position of the extending tip of the intermediate arm portion may be the same as or different from the position of the extending tip of the supporting arm portion. By adjusting the position of the extending tip of the intermediate arm portion, the position of the center of gravity of the entire piezoelectric vibrating piece including the intermediate arm portion can be set to a desired position.

In the fourth aspect, the piezoelectric vibrating piece according to any one of the first to third aspects, a package including an accommodating portion for accommodating the piezoelectric vibrating piece in an airtight state, and a support arm portion are contained in the bottom surface of the accommodating portion. Has a conductive adhesive that adheres to.

The piezoelectric vibrating piece is housed in an airtight state in the housing part of the package. Since this piezoelectric vibrator has a pair of intermediate arm portions, a part of the vibration transmitted from the vibrating arm portion to the support arm portion via the base portion is absorbed as the vibration of the intermediate arm portion. Vibration leakage from the vibrating arm to the supporting arm is suppressed, and good vibration characteristics can be obtained as a piezoelectric vibrator.

In the fifth aspect, in the fourth aspect, the intermediate arm portion is in non-contact with the package.

Since the intermediate arm portion is not in contact with the package, the vibration characteristic of the piezoelectric vibrator, in which the vibration of the intermediate arm portion is transmitted to the package, can be further improved.

In the sixth aspect, the piezoelectric vibrator of the fourth or fifth aspect is provided, and the piezoelectric vibrator is electrically connected to an integrated circuit as an oscillator.

A piezoelectric oscillator electrically connected to an integrated circuit as an oscillator has a pair of intermediate arms. Since a part of the vibration transmitted from the vibrating arm to the supporting arm via the base is absorbed as the vibration of the intermediate arm, the vibration leakage from the vibrating arm to the supporting arm is suppressed, which is good as an oscillator. Vibration characteristics can be obtained.

In the seventh aspect, the piezoelectric vibrator of the fourth or fifth aspect is provided, and the piezoelectric vibrator is electrically connected to the time measuring unit.

The piezoelectric vibrator electrically connected to the timekeeping portion has a pair of intermediate arms. Since a part of the vibration transmitted from the vibrating arm to the supporting arm via the base is absorbed as the vibration of the intermediate arm, the vibration leakage from the vibrating arm to the supporting arm is suppressed, and as an electronic device, Good timing characteristics can be obtained.

In the eighth aspect, the piezoelectric vibrator of the fourth or fifth aspect is provided, and the piezoelectric vibrator is electrically connected to the filter unit.

The piezoelectric vibrator electrically connected to the filter portion has a pair of intermediate arm portions. Since a part of the vibration transmitted from the vibrating arm to the supporting arm via the base is absorbed as the vibration of the intermediate arm, the vibration leakage from the vibrating arm to the supporting arm is suppressed, and the radio clock can be used as a radio clock. Good characteristics can be obtained.

In the present application, vibration leakage from the vibrating arm portion to the supporting arm portion can be suppressed.

FIG. 1 is a side view showing the piezoelectric vibration piece of the first embodiment. FIG. 2 is a plan view showing the piezoelectric vibration piece of the first embodiment. FIG. 3 is a side view showing the piezoelectric vibration piece of the first embodiment. FIG. 4 is a perspective view showing the piezoelectric vibrator of the first embodiment. FIG. 5 is an exploded perspective view showing the piezoelectric vibrator of the first embodiment. FIG. 6 is a plan view showing the internal structure of the piezoelectric vibrator of the first embodiment. FIG. 7 is a sectional view taken along line 7-7 of FIG. 4 showing the piezoelectric vibrator of the first embodiment. FIG. 8 is a flowchart showing a process of manufacturing the piezoelectric vibrating piece of the first embodiment. FIG. 9 is an explanatory diagram showing the steps of manufacturing the piezoelectric vibrating piece of the first embodiment in order from (A) to (E). FIG. 10 is an explanatory diagram showing the steps of adhering the piezoelectric vibrating piece to the cavity of the piezoelectric vibrator in the first embodiment in order from (A) to (C). FIG. 11 is a plan view showing a piezoelectric vibration piece of a comparative example. FIG. 12 is a plan view showing the piezoelectric vibration piece of the second embodiment. FIG. 13 is a plan view showing the piezoelectric vibration piece of the third embodiment. FIG. 14 is a plan view showing the piezoelectric vibration piece of the fourth embodiment. FIG. 15 is a plan view showing the piezoelectric vibration piece of the fifth embodiment. FIG. 16 is a configuration diagram showing an oscillator using the piezoelectric vibrator of the embodiment of the present application. FIG. 17 is a configuration diagram showing an electronic device using the piezoelectric vibrator of the embodiment of the present application. FIG. 18 is a configuration diagram showing a radio clock using the piezoelectric vibrator of the embodiment of the present application.

The piezoelectric vibration piece 22 and the piezoelectric vibrator 42 according to the first embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the width direction, the longitudinal direction, and the thickness direction of the piezoelectric vibrating piece 22 are deviated from each other and are indicated by arrows W, L, and T. Further, in the drawings, three arrows X, Y, and Z orthogonal to each other are shown. In FIGS. 1 to 3, the arrow X and the opposite −X direction correspond to the width direction, the arrow Y and the opposite −Y direction correspond to the longitudinal direction, and the arrow Z and the opposite −Z direction correspond to the thickness direction. ..

The piezoelectric vibration piece 22 is made of a piezoelectric material such as quartz, lithium tantalate, or lithium niobate, and is a member that vibrates when a predetermined voltage is applied. As will be described later, the shape of the piezoelectric vibrating piece 22, particularly the shape having a pair of vibrating arm portions 26, may be referred to as a tuning fork type.

As shown in FIGS. 1 and 2, the piezoelectric vibrating piece 22 has a plate-shaped base 24. In the present embodiment, the base portion 24 has a rectangular shape with the long side 24L in the arrow W direction when viewed in the thickness direction (arrow T1 direction). That is, the direction of the long side 24L of the base 24 coincides with the width direction of the piezoelectric vibrating piece 22.

A pair (two) vibrating arm portions 26 extend from the base portion 24 in the Y direction of the arrow (first direction). The two vibrating arms 26 are parallel to each other and are arranged in the direction of arrow W in a plan view. In the present embodiment, each of the vibrating arm portions 26 is integrally molded with the base portion 24, and extends from one of the long sides 24L of the base portion 24.

Further, a pair (two) of support arm portions 28 extend from the base portion 24. Each of the support arm portions 28 is located outside both of the arrangement directions (arrow W direction) of the vibrating arm portions 26 in a plan view.

In the present embodiment, the support arm portion 28 has a first extending portion 30A extending outward in the width direction from each of the short sides 24S of the base portion 24, and an arrow from the extending end portion of the first extending portion 30A. It has a shape having a second extending portion 30B extending in the Y direction. The second extending portion 30B of the supporting arm portion 28 is located outside both of the arrangement directions of the vibrating arm portions 26 (direction of arrow W) and parallel to the vibrating arm portion 26. The extension tip 28T of the support arm 28 is located closer to the base 24 than the extension tip 26T of the vibrating arm 26.

Further, a pair (two) of intermediate arm portions 32 extend from the base portion 24. Each of the intermediate arm portions 32 is located between the vibrating arm portion 26 and the support arm portion 28 in a plan view. In the present embodiment, the intermediate arm portion 32 extends in the arrow Y direction from the intermediate position in the extension direction of the first extension portion 30A of the support arm portion 28. That is, the intermediate arm portion 32 has a shape that extends from the base portion 24 via the first extending portion 30A of the supporting arm portion 28.

In the present embodiment, the position of the extension tip 32T of the intermediate arm portion 32 is the same as the position of the extension tip 28T of the support arm portion 28 in the Y direction of the arrow. In other words, as shown in FIG. 3, in the Y direction of the arrow, the extending tip 32T of the intermediate arm portion 32 and the extending tip 28T of the supporting arm portion 28 overlap each other.

As shown in FIG. 2, the piezoelectric vibrating piece 22 has a shape that is line-symmetrical with respect to the center line CL-1 in the width direction at the base 24.

An excitation electrode (not shown) is provided on the surface of the piezoelectric vibration piece 22, and the piezoelectric vibration piece 22 vibrates at a predetermined frequency when a voltage is applied to the excitation electrode. As shown in FIG. 3, in the piezoelectric vibrating piece 22 of the present embodiment, recesses 26H are formed along the first direction on both sides (upper surface 26A and lower surface 26B) of the vibrating arm portion 26 in the thickness direction, and the surface area is increased. It is wide and has a shape that allows the excitation electrode to be provided in a wide range.

As shown in FIGS. 4 to 7, the piezoelectric vibrator 42 has a package 44. In the present embodiment, the package 44 is a rectangular parallelepiped box-shaped member, and the inside is a housing portion 46. The piezoelectric vibrating piece 22 is housed in the accommodating portion 46 in an airtight state.

The package 44 has a package main body 48 in which one surface (upper surface in FIGS. 5 and 7) is open, and a flat plate-shaped closing plate 50 for closing the open portion of the package main body 48. ..

The package main body 48 has a flat plate-shaped package plate 52, a frame-shaped package frame 54, and an annular seal frame 56. In the present embodiment, both the package plate 52 and the package frame 54 are made of ceramic, and for example, ceramic green sheets are superposed and integrally sintered. Further, the seal frame 56 is joined in a state of being overlapped with the package frame 54.

In the present embodiment, the outside of the package plate 52, the outside of the package frame 54, and the outside of the seal frame 56 have the same shape in a plan view (arrow D1 direction view). In the present embodiment, the outer shapes of the package plate 52, the package frame 54, and the seal frame 56 are the same rectangular shape. The four corners of the package body 48 are provided with arcuate notches 48K having a central angle of 90 degrees over the thickness direction.

Further, as shown in FIGS. 5 to 7, the inside of the package frame 54 and the inside of the seal frame 56 have the same shape in a plan view. In the present embodiment, both the inside of the package frame 54 and the inside of the seal frame 56 are rectangular with arcuate corners.

From each of the long sides 54L (see FIG. 5) of the package frame 54, support portions 58 protruding inward of the package frame 54 in a plan view are formed. The support portion 58 is a portion of the bottom surface 44B of the package 44 that supports the piezoelectric vibration piece 22.

As shown in FIG. 6, the position of the support portion 58 in a plan view is a position that overlaps a part of the support arm portion 28 in the piezoelectric vibration piece 22 but does not overlap with a portion other than the support arm portion 28. Therefore, the intermediate arm portion 32 is non-contact with the package 44.

As shown in FIGS. 5 to 7, an electrode pad 60 electrically connected to the piezoelectric vibration piece 22 is provided on the upper surface of the support portion 58. Then, the support arm portion 28 is adhered to the electrode pad 60 by the conductive adhesive 62 on the electrode pad 60. That is, the piezoelectric vibrating piece 22 is attached to the package 44 by electrically connecting and adhering the support arm portion 28 to the support portion 58 of the bottom surface 44B of the package 44 by the conductive adhesive 62. be.

The support portion 58 is provided with a through electrode 64 penetrating the support portion 58, and is piezoelectric from the outside of the piezoelectric vibrator 42 (external electrode 66 described later) through the through electrode 64 and the conductive adhesive 62. A predetermined voltage can be applied to the vibrating piece 22.

A pair of external electrodes 66 are provided on the lower surface of the package plate 52, that is, on the outer surface of the package 44, at intervals in the longitudinal direction of the package plate 52. As shown in FIG. 7, the package plate 52 is provided with a through electrode 65 that penetrates the package plate 52 in the thickness direction, and the through electrode 65 and the through electrode 64 are electrically connected by the electrode 67. That is, the electrode pad 60 and the external electrode 66 are electrically connected via the through electrode 65, the electrode 67, and the through electrode 64.

As shown in FIGS. 4, 5 and 7, the block plate 50 is a member formed in a flat plate shape by a conductive material. In a plan view, the outer shape of the closing plate 50 is smaller than the outer shape of the seal frame 56. By joining the closing plate 50 to the seal frame 56, the space between the package main body 48 and the closing plate 50 becomes an accommodating portion 46 for accommodating the piezoelectric vibration piece 22.

The package plate 52 and the package frame 54 are made of ceramics, for example, as described above. More specifically, for example, HTCC (High Temperature Co-Fired Ceramic) made of alumina, LTCC (Low Temperature Co-Fired Ceramic) made of glass ceramic, and the like can be mentioned.

Further, as the material of the seal frame 56, a material having conductivity, for example, a nickel-based alloy or the like can be mentioned. More specifically, it may be selected from Kovar, Elinvar, Invar, 42-alloy and the like. In particular, as the material of the seal frame 56, it is preferable to select a material having a coefficient of thermal expansion close to that of the package plate 52 package frame 54 made of ceramic. For example, when alumina having a thermal expansion coefficient of 6.8 × 10-6 / ° C. is used as the package plate 52 package frame 54, Kovar having a thermal expansion coefficient of 5.2 × 10-6 / ° C. is used as the seal frame 56. Alternatively, it is preferable to use a 42-alloy having a coefficient of thermal expansion of 4.5 to 6.5 × 10-6 / ° C.

Examples of the method for attaching the closing plate 50 to the package body 48 include baking with a brazing material such as silver brazing or a soldering material, seam welding, laser welding, ultrasonic welding and the like.

Next, a method of manufacturing the piezoelectric vibration piece 22 will be described.

First, a rough Lambert crystal is sliced to obtain a wafer S having a certain thickness. After wrapping and roughening the wafer S, the work-altered layer is removed by etching, and then mirror polishing such as polishing is performed to prepare a wafer S having a predetermined thickness (for example, 80 μm) (step in FIG. 8). S1).

Next, as shown in FIG. 9A, an etching protective film 70 and an outer photoresist film 73 are formed on both sides of the wafer S (step S2 shown in FIG. 8). The etching protective film 70 is a laminated film in which, for example, an etching protective film 71 in which chrome (Cr) is formed into a film of several tens of nm and an etching protective film 72 in which gold (Au) is formed into a film of several tens of nm are sequentially laminated.

In this step S2, first, the etching protective film 71 and the etching protective film 72 are sequentially formed on both surfaces of the wafer S by a sputtering method, a vapor deposition method, or the like, respectively.

Next, a resist material is applied onto the etching protective film 70 by a spin coating method or the like to form an outer photoresist film 73.

As the resist material used in this embodiment, a rubber-based negative resist mainly composed of cyclized rubber (for example, cyclized isoprene) can be preferably used. The rubber-based negative resist is a resist purified by dissolving cyclized rubber in an organic solvent, further adding a bisazido photosensitive agent, filtering, and removing impurities.

Next, both sides of the wafer S on which the etching protective film 70 and the outer photoresist film 73 are formed are collectively exposed and developed using a photomask on which the outer pattern is drawn. As a result, as shown in FIG. 9B, the outer shape pattern 73A is formed on the outer shape photoresist film 73 (step S3 in FIG. 8). The outer shape pattern 73A has a shape along the outer shape of the target piezoelectric vibrating piece 22.

Next, etching is performed using the outer photoresist film 73 on which the outer pattern 73A is formed as a mask, and only the etching protective film 72 of the unmasked etching protective film 70 is selectively removed (step S4 in FIG. 8). ..

Next, after the etching process, the outer photoresist film 73 on which the outer pattern 73A is formed is peeled off (step S5 in FIG. 8). As a result, the outer pattern 72A (see FIG. 9C) is formed on the etching protective film 72.

For the etching process, a wet etching method in which the wafer S on which the etching protective film 70 and the outer photoresist film 73 are formed is immersed in a chemical solution can be used. Specifically, for example, the etching protective film 72 on which gold (Au) is formed can be etched using iodine as a chemical solution.

Next, the etching process is performed using the etching protective film 72 as a mask, and the etching protective film 71 of the unmasked etching protective film 70 is selectively removed. As a result, as shown in FIG. 9C, the outer pattern 71A is formed on the etching protective film 71. For the etching process, a wet etching method in which the wafer S on which the etching protective film 71 is formed is immersed in a chemical solution can be used. Specifically, for example, the etching protective film 71 on which chromium (Cr) is formed can be etched using potassium ferricyanide as a chemical solution.

Next, as shown in FIG. 9D, etching processing is performed using the outer pattern 70A as a mask, and the unmasked wafer S is selectively removed (step S6 shown in FIG. 8, etching step). For this etching process, a wet etching method can be used in which the wafer S on which the outer pattern 70A is formed is immersed in a chemical solution. For example, a wafer made of quartz can be etched using hydrofluoric acid as a chemical solution. In this case, the etching time can be about 10 hours.

Next, after the etching process, the etching protective film 70 on which the outer pattern 70A is formed is peeled off (step S7 shown in FIG. 8, mask removing step). As a result, as shown in FIG. 9E, the piezoelectric vibrating piece 22 is obtained.

The piezoelectric vibrating piece 22 thus obtained is attached to the package 44 by the steps shown in order in FIG.

First, as shown in FIG. 10A, the uncured conductive adhesive 62 is applied to the upper surface of the electrode pad 60 of the support portion 58 provided on the package frame 54. In this embodiment, an adhesive having conductivity and thermosetting property is used.

Next, as shown in FIG. 10B, a part of the support arm portion 28 of the piezoelectric vibrating piece 22 is brought into contact with the uncured conductive adhesive 62 in the support portion 58.

Next, the uncured conductive adhesive 62 is heated and cured. As a result, the support arm portion 28 of the piezoelectric vibrating piece 22 is adhered to the support portion 58 of the package 44 in a state of being supported by the cured conductive adhesive 62. Then, as shown in FIG. 10C, the piezoelectric vibrating piece 22 is supported in a state parallel to the lower surface of the package frame 54, and the pair of supporting arm portions 28 are conductively adhered to the electrode pads 60, respectively. It is mounted in a state of being electrically connected via the agent 62.

Next, the operation of this embodiment will be described.

In the present embodiment, a pair of vibrating arm portions 26 vibrate in the piezoelectric vibrating piece 22 by applying a predetermined voltage from the external electrode 66 to the piezoelectric vibrating piece 22 through the through electrode 64 and the conductive adhesive 62. .. Then, this vibration is converted into an electric signal and taken out to the outside of the piezoelectric vibrator 42.

In this embodiment, it has a pair of intermediate arm portions 32. Each of the pair of intermediate arm portions 32 extends from the base 24 in the first direction between each of the pair of vibrating arm portions 26 and each of the pair of support arm portions 28. When the vibrating arm portion 26 vibrates, a part of this vibration also tries to be transmitted to the support arm portion 28.

However, the intermediate arm portion 32 extends from the middle of the vibration transmission path from the vibrating arm portion 26 to the support arm portion 28 via the base portion 24. Therefore, a part of the vibration transmitted from the vibrating arm portion 26 to the supporting arm portion 28 is absorbed as the vibration of the intermediate arm portion 32.

Here, FIG. 11 shows the piezoelectric vibration piece 92 of the comparative example. The piezoelectric vibrating piece 92 has a structure that does not have an intermediate arm portion 32 as compared with the piezoelectric vibrating piece 22 of the first embodiment. Since the piezoelectric vibration piece 92 of the comparative example does not have the intermediate arm portion 32, the vibration of the vibrating arm portion 26 is easily transmitted to the support arm portion 28.

In the piezoelectric vibration piece 92 of the comparative example, in order to suppress the vibration transmission from the vibrating arm portion 26 to the supporting arm portion 28, for example, the first extending portion 30A may be made thinner or the base portion 24 may be made thicker. Is also possible. However, if the first extension portion 30A is made thin, the durability is lowered. Further, when the base portion 24 is made thicker, the position of the center of gravity of the piezoelectric vibrating piece 92 in the longitudinal direction (arrow L1 direction) is biased toward the base portion 24 side.

On the other hand, in the present embodiment, the vibration transmitted from the vibrating arm portion 26 to the supporting arm portion 28 is smaller than that of the structure without the intermediate arm portion 32 such as the piezoelectric vibration piece 92 of the comparative example. By suppressing the vibration leakage from the vibrating arm portion 26 to the supporting arm portion 28 in this way, the vibration characteristics of the piezoelectric vibration piece 22 and the piezoelectric vibrator 42 are improved.

Moreover, in the present embodiment, it is not necessary to make the first extending portion 30A thinner or the base 24 thicker in order to suppress the vibration transmission from the vibrating arm portion 26 to the supporting arm portion 28. Since the first extending portion 30A is not thinned, the durability does not decrease. Further, since the base portion 24 is not thickened, the position of the center of gravity of the piezoelectric vibrating piece 92 is not biased toward the base portion 24.

The piezoelectric vibrator 42 has a structure in which the intermediate arm portion 32 of the piezoelectric vibrating piece 22 does not come into contact with the package 44. Even if the intermediate arm portion 32 vibrates, this vibration is not transmitted to the package 44, so that the piezoelectric vibrator 42 of the present embodiment vibrates as compared with the piezoelectric vibrator having a structure in which the intermediate arm portion 32 contacts the package 44. The characteristics are good.

Next, the second to fifth embodiments will be described. In the piezoelectric vibration pieces of the second to fifth embodiments, the same elements, members, and the like as those of the piezoelectric vibration pieces 22 of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, in the second to fifth embodiments, the overall structure of the piezoelectric vibrator is the same as that of the piezoelectric vibrator 42 of the first embodiment, and thus the illustration is omitted.

In the piezoelectric vibration piece 222 of the second embodiment shown in FIG. 12, a pair of intermediate arm portions 224 extend in the first direction from the base portion 24, but the extending tips 224T of the intermediate arm portions 224 respectively. The position is the same as the position of the extending tip 26T of the vibrating arm portion 26.

In the piezoelectric vibration piece 232 of the third embodiment shown in FIG. 13, a pair of intermediate arm portions 234 extend in the first direction from the base portion 24, but the extending tips 234T of the intermediate arm portions 234 respectively. The position is closer to the base 24 than the extending tip 28T of the support arm 28.

In the piezoelectric vibration piece 242 of the fourth embodiment shown in FIG. 14, as a pair of intermediate arm portions 244, the intermediate arm portion 246 extending in the first direction from the base portion 24 and extending in the direction opposite to the first direction. It has an intermediate arm portion 248 to be put out. In the example shown in FIG. 14, the position of the extending tip 246T of the intermediate arm portion 246 is closer to the base 24 than the extending tip 28T of the supporting arm portion 28. In the example shown in FIG. 14, the extension length of the intermediate arm portion 248 from the first extension portion 30A is about the same as the extension length from the first extension portion 30A of the intermediate arm portion 246.

In the piezoelectric vibration piece 252 of the fifth embodiment shown in FIG. 15, a pair of intermediate arm portions 254 extend in the direction opposite to the first direction. The extension length of the intermediate arm portion 254 from the first extension portion 30A is about the same as the extension length of the intermediate arm portion 246 of the fourth embodiment in the example shown in FIG.

As in these second to fifth embodiments, the extension direction of the intermediate arm portion and the position of the extension tip are not particularly limited. By adjusting the extension direction and the position of the extension tip of the intermediate arm portion, the position of the center of gravity in the longitudinal direction (arrow L direction) of the piezoelectric vibrating piece can be adjusted. That is, the extension direction and the position of the extension tip of the intermediate arm portion may be adjusted so as to be the position of the center of gravity where good vibration characteristics can be obtained as the piezoelectric vibration piece.

Further, in the piezoelectric vibrating piece whose center of gravity is adjusted in this way, the posture of the piezoelectric vibrating piece is stabilized when it is housed in the package 44. For example, the piezoelectric vibrating piece and the bottom surface 44B of the package 44 can be maintained in parallel, and the piezoelectric vibrating piece can be accommodated and mounted in the package 44.

The piezoelectric vibration pieces 22, 222, 232, 242, and 252 of each of the above embodiments can be mounted on various devices.

For example, FIG. 16 shows the oscillator 100. The oscillator 100 uses the piezoelectric oscillator 42 as an oscillator electrically connected to the integrated circuit 101. The oscillator 100 includes a substrate 103 on which an electronic component 102 such as a capacitor is mounted. An integrated circuit 101 for an oscillator is mounted on the substrate 103, and a piezoelectric vibrator 42 is mounted in the vicinity of the integrated circuit 101. The electronic component 102, the integrated circuit 101, and the piezoelectric vibrator 42 are electrically connected by a wiring pattern (not shown). Each component is also molded with a resin (not shown).

In the oscillator 100 configured as described above, when a voltage is applied to the piezoelectric vibrator 42, the piezoelectric vibration piece 22 in the piezoelectric vibrator 42 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibration piece 22, and is input to the integrated circuit 101 as an electric signal. The input electric signal is subjected to various processing by the integrated circuit 101 and output as a frequency signal. As a result, the piezoelectric vibrator 42 functions as an oscillator.

Further, by selectively setting the configuration of the integrated circuit 101, for example, an RTC (real-time clock) module or the like according to a request, the operating date and time of the device or an external device in addition to the single-function oscillator for a clock or the like can be selected. It is possible to add a function to control the clock and provide a time, a calendar, and the like.

Since such an oscillator 100 includes any of the piezoelectric vibrators of each embodiment, it is possible to obtain an oscillator 100 having good vibration characteristics and excellent reliability.

Next, FIG. 17 shows a mobile information device 110 as an example of an electronic device. The mobile information device 110 is, for example, a mobile phone and includes a display unit (display) 115 for displaying predetermined information. It is also possible to communicate with an external base station or communication master unit. In addition, speakers and microphones can transmit and input voice to the user.

The portable information device 110 includes a piezoelectric vibrator 42 and a power supply unit 111 for supplying electric power. The power supply unit 111 includes, for example, a lithium secondary battery. A control unit 112, a timekeeping unit 113, a communication unit 114, a display unit 115, and a voltage detection unit 116 are connected to the power supply unit 111 as functional units.

The control unit 112 performs various controls on the mobile information device 110. The timekeeping unit 113 counts the time and the like. The communication unit 114 communicates with the outside of the mobile information device 110. The display unit 115 displays various information in the mobile information device 110. The voltage detection unit 116 detects the voltage of each functional unit in the portable information device 110, and the power supply unit 111 supplies electric power to each functional unit.

More specifically, the control unit 112 controls each functional unit to control the operation of the entire system, such as transmission and reception of voice data, measurement and display of the current time, and the like. Further, the control unit 112 is used as a Read Only Memory (ROM) in which a program is written in advance, a Central Pricing Unit (CPU) that reads and executes a program written in this ROM, and a work area of this CPU. It is equipped with a Random Access Memory (RAM) and the like.

The timing unit 113 includes an integrated circuit including an oscillation circuit, a register circuit, a counter circuit, an interface circuit, and the like, and a piezoelectric vibrator 42. When a voltage is applied to the piezoelectric vibrator 42, the piezoelectric vibration piece 22 vibrates, and this vibration is converted into an electric signal by the piezoelectric characteristics of the crystal and input to the oscillation circuit as an electric signal. The output of the oscillation circuit is binarized and counted by the register circuit and the counter circuit. Then, signals are transmitted and received to and from the control unit 112 via the interface circuit, and the current time, the current date, calendar information, and the like are displayed on the display unit 115.

The communication unit 114 includes a radio unit 117, a voice processing unit 118, a switching unit 119, an amplification unit 120, a voice input / output unit 121, a telephone number input unit 122, a ringtone generation unit 123, and a call control memory unit 124. The radio unit 117 exchanges various data such as voice data with the base station via the antenna 125. The voice processing unit 118 encodes and duplicates the voice signal input from the radio unit 117 or the amplification unit 120. The amplification unit 120 amplifies the signal input from the voice processing unit 118 or the voice input / output unit 121 to a predetermined level. The voice input / output unit 121 includes a speaker, a microphone, and the like, and expands the ringtone and the received voice, and collects the voice.

The ringtone generation unit 123 generates a ringtone in response to a call from the base station. When the switching unit 119 receives a call, the amplification unit 120 connected to the voice processing unit 118 is switched to the ringtone generation unit 123, so that the ringtone generated by the ringtone generation unit 123 is voiced via the amplification unit 120. It is output to the input / output unit 121. The call control memory unit 124 stores a program related to incoming / outgoing call control for communication. Further, the telephone number input unit 122 includes, for example, a number key from 0 to 9 and other keys, and the user can input a telephone number or the like of a call destination by pressing these keys or the like.

When the voltage applied to each functional unit such as the control unit 112 by the power supply unit 111 falls below a predetermined value, the voltage detection unit 116 detects the voltage drop and notifies the control unit 112. .. The predetermined voltage value at this time is a value preset as the minimum voltage required for the communication unit 114 to operate stably, and is, for example, about 3V. Upon receiving the notification of the voltage drop from the voltage detection unit 116, the control unit 112 prohibits the operations of the radio unit 117, the voice processing unit 118, the switching unit 119, and the ringtone generation unit 123. In particular, it is essential to stop the operation of the wireless unit 117, which consumes a large amount of power. Further, the display unit 115 indicates that the communication unit 114 has become unusable due to insufficient battery power.

That is, the voltage detection unit 116 and the control unit 112 can prohibit the operation of the communication unit 114 and display that fact on the display unit 115. This display may be a text message, but as a more intuitive display, the telephone icon displayed at the upper part of the display surface of the display unit 115 may be marked with a cross. By providing the power cutoff unit 126 capable of selectively cutting off the power supply of the portion related to the function of the communication unit 114, the function of the communication unit 114 can be stopped more reliably.

Since the portable information device 110 includes the piezoelectric vibrator according to any one of the first to fifth embodiments, the portable information device 110 can be made highly reliable due to the excellent vibration characteristics of the piezoelectric vibrator. can.

Next, FIG. 18 shows a radio clock 130. The radio-controlled clock 130 includes a piezoelectric vibrator 42 electrically connected to the filter unit 131. It also has a function to receive standard radio waves including clock information, automatically correct the time, and display it.

The radio-controlled clock 130 includes a filter unit 131, an antenna 132, an amplifier 133, a detection rectifier circuit 134, a waveform shaping circuit 135, a CPU 136, a Real Time Clock (RCT) 137, and a crystal oscillator unit 138 and 139.

The antenna 132 receives a standard radio wave, for example, a long wave radio wave of 40 kHz or 60 kHz in Japan. The received standard radio wave is amplified by the amplifier 133, and is filtered and tuned by the filter unit 131 having a plurality of piezoelectric vibrators 42. The piezoelectric vibrator 42 used in the radio-controlled clock 130 includes crystal oscillators 138 and 139 having a resonance frequency of 40 kHz or 60 kHz, respectively.

The filtered signal having a predetermined frequency is detected and demodulated by the detection and rectification circuit 134. Subsequently, the time code is taken out via the waveform shaping circuit 135 and counted by the CPU 136. The CPU 136 reads information such as the year, integrated date, day of the week, and time at that time. The read information is reflected in RTC137, and accurate time information is displayed.

Since the radio-controlled clock 130 also includes the piezoelectric vibrator according to any one of the first to fifth embodiments, the radio-controlled clock 130 can be made highly reliable due to the excellent vibration characteristics of the piezoelectric vibrator. ..

22 Differential vibrating piece 24 Base 26 Vibrating arm 26T Extended tip of vibrating arm 28 Supporting arm 28T Extended tip of supporting arm 32 Intermediate arm 32T Extended tip of intermediate arm 42 Hydraulic vibrator 44 Package 44B Bottom 46 Housing 48 Package body 62 Conductive adhesive 100 Oscillator 110 Portable information device (example of electronic device)
113 Measuring part 130 Radio clock 131 Filter part 222 Piezoelectric vibration piece 224 Intermediate arm part 224T Intermediate arm part extension tip 232 Piezoelectric vibration piece 234 Intermediate arm part 234T Intermediate arm part extension tip 242 Piezoelectric vibration piece 244 Intermediate arm part 246 Intermediate arm 246T Extension tip of intermediate arm 248 Intermediate arm 252 Piezoelectric vibration piece 254 Intermediate arm

Claims (7)

Piezoelectric vibrating pieces made of piezoelectric material
At the base,
A pair of vibrating arms extending in the first direction from the base,
A first extension portion extending in the alignment direction from the base portion on both outer sides of the pair of vibrating arm portions in the alignment direction, and a second extension portion extending in the first direction from the first extension portion. , And a pair of support arms fixed to the package in which the piezoelectric vibrating piece is housed in the second extension .
Each of the pair of vibrating arms and the pair of support arms extends from the first extension in at least one of the first direction and the opposite direction in the alignment direction , and is included in the package. On the other hand, a pair of middle arms that are not fixed ,
Piezoelectric vibrating piece with . The piezoelectric vibrating piece according to claim 1, wherein the position of the extending tip of the intermediate arm portion is the same as the position of the extending tip of the pair of supporting arms in the first direction. The piezoelectric vibrating piece according to claim 1, wherein the position of the extending tip of the intermediate arm portion is different from the position of the extending tip of the pair of supporting arms in the first direction or the opposite direction. The piezoelectric vibrating piece according to any one of claims 1 to 3 and
The package including the accommodating portion for accommodating the piezoelectric vibrating piece in an airtight state, and the package.
A conductive adhesive that adheres the support arm to the bottom surface of the housing,
Piezoelectric oscillator with. An oscillator comprising the piezoelectric vibrator according to claim 4 , wherein the piezoelectric vibrator is electrically connected to an integrated circuit as an oscillator. An electronic device comprising the piezoelectric vibrator according to claim 4 , wherein the piezoelectric vibrator is electrically connected to a time measuring unit. A radio-controlled timepiece comprising the piezoelectric vibrator according to claim 4 , wherein the piezoelectric vibrator is electrically connected to a filter unit.

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