A quartz crystal vibrator element having the weight section is provided with the intermediate weight section formed to have an arm width W1 larger (thicker) than the arm width W of the vibrating arm section and smaller (thinner) than the arm width W2 of the tip weight section, thereby making the intermediate weight section follow the vibration (the amplitude) of the vibrating arm section. Further, the tip weight section formed to have an arm width W2 larger (thicker) than the arm width W1 of the intermediate weight section is provided, thereby making the tip weight section follow the vibration (the amplitude) of the vibrating arm section and the intermediate weight section. Therefore, the vibration characteristics of the vibrating arm section can be stabilized.

BACKGROUND

1. Technical Field

The present invention relates to a vibrator element, a vibrator and an oscillator each equipped with the vibrator element, and an electronic apparatus equipped with the oscillator.

2. Related Art

In the past, there has been disclosed a vibrator element having a weight section with an arm width rapidly increased to be large (thick) compared to the arm width of the vibrating arm section, the weight section being formed at the tip portion of the vibrating arm section of the vibrator element, to thereby achieve stabilization of the vibration of the vibrating arm section and the frequency of the vibrator element (see, e.g., JP-A-2005-5896 (pp. 5-7, FIGS. 1-5) and JP-A-2009-27711 (pp. 5-6, FIG. 1)). Further, there has been disclosed a vibrator element having the weight section formed to have an arm width gradually increasing from the tip portion of the vibrating arm section (see, e.g., JP-A-2006-311090 (pp. 6-7, FIG. 3)).

However, in the vibrator element of the related art, there is a case in which the weight section is difficult to follow the vibration (the amplitude) of the vibrating arm section, and if the weight section having a width rapidly increasing to be large (thick) is formed at the tip portion of the vibrating arm section, there arises a problem that the weight section fails to follow the vibration (the amplitude) of the vibrating arm section to thereby vibrate differently from the vibration of the vibrating arm section due to the inertia, which makes the vibration of the vibrating arm section unstable, or varies the vibrational frequency of the vibrating arm section. Further, in the case of providing the vibrating arm section with the weight section having the arm width gradually increasing from the tip portion of the vibrating arm section, although the vibration of the vibrating arm section is hardly destabilized, there arises a problem that the effect of lowering the frequency due to the formation of the weight section at the tip portion is degraded.

SUMMARY

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

Application Example 1

According to this application example of the invention, there is provided a vibrator element including a base portion, a plurality of vibrating arm sections extending from the base portion, an elongated groove section formed along a longitudinal direction of each of the vibrating arm sections, an intermediate weight section having an arm width larger than an arm width of each of the vibrating arm sections, and formed on a tip side of each of the vibrating arm sections, and a tip weight section having an arm width larger than the arm width of the intermediate weight section, and formed on a tip side of the intermediate weight section.

According to this application example of the invention, the vibrator element is provided with the intermediate weight section formed to have an arm width larger (thicker) than the arm width of the vibrating arm section and smaller (thinner) than the arm width of the tip weight section, thereby making the intermediate weight section follow the vibration (the amplitude) of the vibrating arm section. Further, the tip weight section formed to have an arm width larger (thicker) than the arm width of the intermediate weight section is provided, thereby making the tip weight section follow the vibration (the amplitude) of the vibrating arm section and the intermediate weight section. Therefore, the vibration of the vibrating arm section and the vibrational frequency of the vibrator element can be stabilized. Further, the vibrator element is provided with the intermediate weight section to thereby obtain a frequency reduction effect as well.

Application Example 2

According to this application example of the invention, in the vibrator element of the above application example of the invention, it is preferable to further include a first widening section disposed between the vibrating arm section and the intermediate weight section and having an arm width gradually increasing from the arm width of the vibrating arm section to the arm width of the intermediate weight section.

According to this application example of the invention, by gradually increasing the arm width of the first widening section from the arm width of the vibrating arm section to the arm width of the intermediate weight section in accordance with the difference between the arm width of the vibrating arm section and the arm width of the intermediate weight section, the quartz crystal vibrator element can obtain an advantage of suppressing the asymmetry property of the etching due to the anisotropy of, for example, the vibrator element material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the vibrating arm section and the intermediate weight section. Thus, the balance can be maintained between the vibrating arm sections, and thus the vibration characteristics of the vibrator element can be stabilized.

Application Example 3

According to this application example of the invention, in the vibrator element of the above application example of the invention, it is preferable to further include a second widening section disposed between the intermediate weight section and the tip weight section, and having an arm width gradually increasing from the arm width of the intermediate weight section to the arm width of the tip weight section.

According to this application example of the invention, by gradually increasing the arm width of the second widening section from the arm width of the intermediate weight section to the arm width of the tip weight section in accordance with the difference between the arm width of the intermediate weight section and the arm width of the tip weight section, the quartz crystal vibrator element can obtain an advantage of suppressing the asymmetry property of the etching due to the anisotropy of, for example, the vibrator element material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the intermediate weight section and the tip weight section. Thus, the highly accurate balance can be maintained between the vibrating arm sections, and thus the vibration characteristics of the vibrator element can further be stabilized.

Application Example 4

According to this application example of the invention, there is provided a vibrator including the vibrator element according to any one of the application examples of the invention described above, and a package adapted to house the vibrator element.

According to this application example of the invention, since the vibrator element has the intermediate weight section, the intermediate weight section is made to follow the vibration (the amplitude) of the vibrating arm section, and further, since the vibrator element further has the tip weight section, the tip weight section is made to follow the vibration (the amplitude) of the vibrating arm section and the intermediate weight section. Thus, the vibrator has the stabilized vibrational frequency, and can obtain the frequency reduction effect.

Application Example 5

According to this application example of the invention, there is provided an oscillator including the vibrator element according to any one of the application examples of the invention described above, a circuit section electrically connected to the vibrator element, and a package adapted to house the vibrator element and the circuit section.

According to this application example of the invention, since the vibrator element having the stabilized vibrational frequency and the frequency reduction effect and the circuit section are provided, the oscillator can be provided with superior oscillation characteristics.

Application Example 6

According to this application example of the invention, there is provided an electronic apparatus including the vibrator element according to any one of the application examples of the invention described above, and a circuit section electrically connected to the vibrator element.

According to this application example of the invention, since the vibrator element having the stabilized vibrational frequency and the frequency reduction effect and the circuit section are provided, the electronic apparatus can achieve a high reliability.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the explanation of the following embodiments, a quartz crystal vibrator element using quartz crystal as a piezoelectric material is cited as an example of the vibrator element. Further, the quartz crystal vibrator (the vibrator) and a quartz crystal oscillator (the oscillator) each equipped with the quartz crystal vibrator element, and an electronic apparatus equipped with the quartz crystal oscillator will be explained.

First Embodiment

A first embodiment of the invention will hereinafter be explained with reference toFIGS. 1A through 1C.

FIG. 1Ais a schematic plan view showing the quartz crystal vibrator element according to the first embodiment.FIG. 1Bis a partial enlarged view of the quartz crystal vibrator element shown inFIG. 1A.FIG. 1Cis a cross-sectional view along the line A-A shown inFIG. 1A.

As shown inFIG. 1A, the quartz crystal vibrator element1as the vibrator element is provided with the base portion2, two vibrating arm sections3, two intermediate weight sections4, two tip weight sections5, elongated groove sections6, a coupling section11, and a support section12. The quartz crystal vibrator element1has a Z-axis as an optical axis of the quartz crystal column, an X-axis as an electrical axis perpendicular to the Z-axis, and a Y-axis as a mechanical axis perpendicular to the x-axis, and is cut out from a Z-cut quartz crystal plate along a plane obtained by tilting the X-Y plane 5 degrees from the angle of 0 degree around the X-axis viewed from the intersection (the coordinate origin) between the X-axis and the Y-axis. As shown inFIGS. 1A through 1C, the width direction of the base portion2corresponds to the X-axis, the longitudinal direction of the vibrating arm section3corresponds to a Y′-axis direction, and the thickness direction of the quartz crystal vibrator element1corresponds to a Z′-axis direction.

The coupling section11of the quartz crystal vibrator element1is formed so as to extend from the base portion2. The support section12is formed so as to extend from the coupling section11. The coupling section11is formed to have a dimension in the vertical direction shown in the drawing smaller than the dimension of the base portion2and the dimension of the support section12in the vertical direction shown in the drawing. Thus, cut sections13are formed between the base portion2and the support section12.

The two vibrating arm sections3are formed so as to extend from the base portion2in parallel to each other to have an arm width W (FIG. 1B). It should be noted that the expression of “in parallel to each other” denotes the state in which the respective extending directions of the vibrating arm sections3are parallel to each other. The vibrating arm sections3are formed axisymmetrically about the dashed dotted line denoted by B-B. The two vibrating arm sections3are disposed at a pitch P.

The intermediate weight sections4each have an arm width W1larger than the arm width W of the vibrating arm section3, and are formed on the top side of the vibrating arm sections3. The tip weight sections5each have an arm width W2larger than the arm width W1of the intermediate weight section4, and are formed on the tip side of the intermediate weight sections4. The intermediate weight sections4and the tip weight sections5are each formed axisymmetrically about the dashed dotted line denoted by B-B.

As shown inFIG. 1B, between the vibrating arm section3and the intermediate weight section4there is formed a first widening section7having an arm width gradually increasing from the arm width W of the vibrating arm section3to the arm width W1of the intermediate weight section4. Further, between the intermediate weight section4and the tip weight section5, there is formed a second widening section8for gradually increasing the arm width from the arm width W1of the intermediate weight section4to the arm width W2of the tip weight section5.

In the present embodiment, the positions bisecting the respective arm widths W, W1, and W2are arranged so as to line on the straight line illustrated with the dashed dotted line shown inFIG. 1B. In other words, the vibrating arm section3, the intermediate weight section4, and the tip weight section5are each formed axisymmetrically about the dashed dotted line shown inFIG. 1B. Further, since the tip weight sections5are formed axisymmetrically about the dashed dotted line denoted as B-B inFIG. 1A, the arm width W2of the tip weight section5takes a value smaller than the pitch P of the vibrating arm sections3.

The elongated groove section6is formed along the longitudinal direction of the vibrating arm section3. As shown inFIG. 1C, the elongated groove section6is provided to each of the surfaces having the arm width W. Further, the elongated groove section6is formed axisymmetrically about the dashed dotted line shown inFIG. 1B.

As shown inFIG. 1C, excitation electrodes14a,14bare provided to the respective vibrating arm sections3and the elongated groove sections6. Further, the layouts of the respective excitation electrodes14a,14bare reverse to each other between the vibrating arm section3(the elongated groove sections6) on the left side and the vibrating arm section3(the elongated groove sections6) on the right side. Specifically, the excitation electrode14ais disposed in each of the elongated groove sections6on the left side of the drawing, while the excitation electrode14bis disposed in each of the elongated groove sections6on the right side of the drawing. Further, the excitation electrodes14bare disposed in the vibrating arm section3on the left side of the drawing, while the excitation electrodes14aare disposed in the vibrating arm section3on the right side of the drawing.

The electrical field is generated by making the current flow between the excitation electrode14aand the excitation electrode14b, and the vibrating arm section3vibrates due to the piezoelectric effect to drive the quartz crystal vibrator element1as illustrated with the dashed dotted arrows and the dashed arrows inFIG. 1A.

According to the present embodiment, the quartz crystal vibrator element1is provided with the intermediate weight section4formed to have an arm width W1larger (thicker) than the arm width W of the vibrating arm section3and smaller (thinner) than the arm width W2of the tip weight section5, thereby making the intermediate weight section4follow the vibration (the amplitude) of the vibrating arm section3. Further, the quartz crystal vibrator element1is provided with the tip weight section5formed to have an arm width W2larger (thicker) than the arm width W1of the intermediate weight section4, thereby making the tip weight section5follow the vibration (the amplitude) of the vibrating arm section3and the intermediate weight section4. Thus, the vibration of the vibrating arm section3and the vibrational frequency of the quartz crystal vibrator element1can be stabilized.

Further, by gradually increasing the arm width of the first widening section7from the arm width W of the vibrating arm section3to the arm width W1of the intermediate weight section4in accordance with the difference between the arm width W of the vibrating arm section3and the arm width W1of the intermediate weight section4, the quartz crystal vibrator element1suppresses the asymmetry property of the etching due to the anisotropy of the quartz crystal as the piezoelectric material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the vibrating arm section3and the intermediate weight section4. Thus, balance can be maintained between the two vibrating arm sections3, thereby making it possible to stabilize the vibration characteristics of the quartz crystal vibrator element1.

Further, by gradually increasing the arm width of the second widening section8from the arm width W1of the intermediate weight section4to the arm width W2of the tip weight section5in accordance with the difference between the arm width W1of the intermediate weight section4and the arm width W2of the tip weight section4, the quartz crystal vibrator element1suppresses the asymmetry property of the etching due to the anisotropy of the quartz crystal as the piezoelectric material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the intermediate weight section4and the tip weight section5. Thus, highly accurate balance can be maintained between the two vibrating arm sections3, thereby making it possible to further stabilize the vibration characteristics of the quartz crystal vibrator element1.

Some modified examples regarding the intermediate weight sections4and the tip weight sections5in the first embodiment will hereinafter be explained with reference toFIGS. 2A through 2E.

First Modified Example

FIG. 2Ashows a first modified example. As shown inFIG. 2A, the intermediate weight section4of the first modified example is not formed axisymmetrically about the dashed dotted line, while the tip weight section5is formed axisymmetrically about the dashed dotted line. Further, one end of the intermediate weight section4defining the arm width W1and one end of the tip weight section5defining the arm width W2are formed on the same straight line.

Further, in the first modified example, although it is assumed that the intermediate weight section4is not formed axisymmetrically about the dashed dotted line, the configuration is not limited thereto, but it is also possible to assume that the intermediate weight section4is formed axisymmetrically about the dashed dotted line, while the tip weight section5is not formed axisymmetrically about the dashed dotted line.

Second Modified Example

FIG. 2Bshows a second modified example. As shown inFIG. 2B, the intermediate weight section4of the second modified example is not formed axisymmetrically about the dashed dotted line, while the tip weight section5is formed axisymmetrically about the dashed dotted line similarly to the case of the first modified example.

Further, the difference from the modified example 1 is the point that one end of the intermediate weight section4defining the arm width W1and one end of the vibrating arm section3defining the arm width W are formed on the same straight line.

Further, in the second modified example, although it is assumed that the one end of the intermediate weight section4defining the arm width W1is formed on the same straight line with the one end of the vibrating arm section3defining the arm width W, the configuration is not limited thereto, but it is also possible to assume that the one end of the intermediate weight section4defining the arm width W1is formed on the same straight line with one end of the tip weight section5defining the arm width W2as shown inFIG. 2C.

Third Modified Example

FIG. 2Dshows a third modified example. As shown inFIG. 2D, the intermediate weight section4and the tip weight section5of the third modified example are not formed axisymmetrically about the dashed dotted line. One end of the intermediate weight section4defining the arm width W1and one end of the tip weight section5defining the arm width W2are formed on the same straight line as the one end of the vibrating arm section3defining the arm width W.

Fourth Modified Example

FIG. 2Eshows a fourth modified example. As shown inFIG. 2E, both of the intermediate weight section4and the tip weight section5are not formed axisymmetrically about the dashed dotted line. Further, the difference from the first through third modified examples is the point that the one end and the other end of the vibrating arm section3defining the arm width W, the one end and the other end of the intermediate weight section4defining the arm width W1, and the one end and the other end of the tip weight section5defining the arm width W2are not formed on the same straight lines, respectively.

Further, in the fourth modified example, although it is assumed that both of the intermediate weight section4and the tip weight section5are not formed axisymmetrically about the dashed dotted line, the configuration is not limited thereto, but it is also possible to assume that either one of the intermediate weight section4and the tip weight section5is not formed axisymmetrically about the dashed dotted line, while the other is formed axisymmetrically about the dashed dotted line.

Second Embodiment

A second embodiment of the invention will hereinafter be explained with reference toFIGS. 3A and 3B.

The second embodiment relates to a quartz crystal vibrator using the quartz crystal vibrator element1according to the first embodiment shown inFIGS. 1A through 1C, the constituents identical to those of the first embodiment are denoted by the same reference numerals, and the explanations of the constituents will be omitted.

FIG. 3Ais a schematic plan view showing the quartz crystal vibrator according to the second embodiment.FIG. 3Bis a cross-sectional view along the line C-C shown inFIG. 3A.

The quartz crystal vibrator20according to the second embodiment is provided with a package21for housing the quartz crystal vibrator element1according to the first embodiment.

As shown inFIGS. 3A and 3B, the quartz crystal vibrator20is provided with the quartz crystal vibrator element1and the package21, and the quartz crystal vibrator element1is housed in the package21in an airtight manner. The package21is provided with the base23and the lid member22.

The base23is provided with a base substrate15, layer substrates16,17, a bonding section18, conductive fixing sections25a,25b, external connection terminals26, and a housing chamber27.

The base23is formed by sequentially stacking the layer substrates16,17on the base substrate15, and then forming the bonding section18made of metal, soldering material, glass or the like on the layer substrate17. The base substrate15and the layer substrates16,17are formed of a ceramic sheet made of an aluminum oxide material as an insulating material, for example. The housing chamber27is formed by hollowing out the layer substrates16,17so as to conform with the shape of the housing chamber27, stacking the layer substrates16,17on the base substrate15, and then sintering the constituents.

There are provided two projection sections24formed of the base substrate15extending inside the housing chamber27. On the projection sections24, there are formed the conductive fixing sections25a,25b, respectively. The conductive fixing sections25a,25bare formed by sequentially performing the processes of, for example, tungsten metalizing, nickel plating, and gold plating.

Two external connection terminals26are provided, and are formed on the lower surface of the base substrate15, the outside of the base23, namely the surface opposed to the housing chamber27. The external connection terminals26are formed on the lower surface of the base substrate15by sequentially performing the processes of, for example, tungsten metalizing, nickel plating, and gold plating.

Further, the external connection terminals26are electrically connected to the conductive fixing sections25via, for example, wiring (not shown) provided to the base substrate15.

The support section12of the quartz crystal vibrator element1is provided with mounting electrodes (not shown) and are connected respectively to the excitation electrodes14a,14b. The quartz crystal vibrator element1is fixed to the conductive fixing sections25with an electrically conductive adhesive28, and is disposed inside the housing chamber27provided to the base23. In such a manner as described above, the excitation electrodes14a,14bare electrically connected respectively to the conductive fixing sections25a,25b, and further electrically connected respectively to the external connection terminals26.

The electrically conductive adhesive28is made of, for example, silicon resin, epoxy resin, or polyimide resin, and contains a combination of electrically conductive powder such as silver (Ag) or platinum (Pt).

The base23is bonded to the lid member22with the bonding section18. In such a manner as described above, the quartz crystal vibrator element1is encapsulated in the housing chamber27in an airtight manner with the base23and the lid member22.

The lid member22is made of metal such as iron (Fe), cobalt (Co), or nickel (Ni), an alloy containing a combination of any of these metals, ceramics composed of an aluminum oxide material, or glass.

According to the present embodiment, the quartz crystal vibrator element1provided to the quartz crystal vibrator20is provided with the intermediate weight section4formed to have an arm width W1larger (thicker) than the arm width W of the vibrating arm section3and smaller (thinner) than the arm width W2of the tip weight section5, thereby making the intermediate weight section4follow the vibration (the amplitude) of the vibrating arm section3. Further, since the quartz crystal vibrator element1is provided with the tip weight section5formed to have an arm width W2larger (thicker) than the arm width W1of the intermediate weight section4, thereby making the tip weight section5follow the vibration (the amplitude) of the vibrating arm section3and the intermediate weight section4, it is possible to obtain the quartz crystal vibrator20with the vibration of the vibrating arm section3and the vibrational frequency of the quartz crystal vibrator element1stabilized.

Further, by gradually increasing the arm width of the first widening section7from the arm width W of the vibrating arm section3to the arm width W1of the intermediate weight section4in accordance with the difference between the arm width W of the vibrating arm section3and the arm width W1of the intermediate weight section4, the quartz crystal vibrator element1suppresses the asymmetry property of the etching due to the anisotropy of the quartz crystal as the piezoelectric material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the vibrating arm section3and the intermediate weight section4. Thus, the balance can be maintained between the two vibrating arm sections3, thereby making it possible to obtain the quartz crystal vibrator20, which stabilizes the vibration characteristics of the quartz crystal vibrator element1.

Further, by gradually increasing the arm width of the second widening section8from the arm width W1of the intermediate weight section4to the arm width W2of the tip weight section5in accordance with the difference between the arm width W1of the intermediate weight section4and the arm width W2of the tip weight section5, the quartz crystal vibrator element1suppresses the asymmetry property of the etching due to the anisotropy of the quartz crystal as the piezoelectric material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the intermediate weight section4and the tip weight section5. Thus, the highly accurate balance can be maintained between the two vibrating arm sections3, thereby making it possible to obtain the quartz crystal vibrator20, which further stabilizes the vibration characteristics of the quartz crystal vibrator element1.

Third Embodiment

A third embodiment of the invention will hereinafter be explained with reference toFIG. 4.

The third embodiment relates to a quartz crystal oscillator using the quartz crystal vibrator element1according to the first embodiment shown inFIGS. 1A through 1C, the constituents identical to those of the first embodiment are denoted by the same reference numerals, and the explanations of the constituents will be omitted.

The point in which the quartz crystal oscillator according to the third embodiment is different from the quartz crystal vibrator20according to the second embodiment is that the quartz crystal oscillator is further provided with a drive circuit (a circuit section) for driving the quartz crystal vibrator20.

FIG. 4is a schematic cross-sectional view showing the quartz crystal oscillator according to the third embodiment. As shown inFIG. 4, the quartz crystal oscillator30is provided with the quartz crystal vibrator element1, the package21, and the drive circuit (the circuit section)31electrically connected to the quartz crystal vibrator element1. The quartz crystal vibrator element1and the drive circuit31are housed in the package21in an airtight manner. The package21is provided with the base23and the lid member22.

The base23is provided with a layer substrate34. The base23is formed by sequentially stacking the layer substrates34,16, and17on the base substrate15, and then forming the bonding section18made of metal, soldering material, glass or the like on the layer substrate17.

The drive circuit31is die-attached to the surface of the base substrate15, and is connected to the internal connection terminals33via bonding wires32.

The conductive fixing sections25are formed on the projection sections24of the base substrate15inside the housing chamber27. A plurality of internal connection terminals33is provided, and is formed on the upper surface of the base substrate15, which is the inside of the base23, namely inside the housing chamber27. The internal connection terminals33are formed on the upper surface of the base substrate15by sequentially performing the processes of, for example, tungsten metalizing, nickel plating, and gold plating.

Further, the internal connection terminals33are electrically connected to the conductive fixing sections25and the external connection terminals26via, for example, wiring (not shown) provided to the base substrate15.

According to the present embodiment, the quartz crystal vibrator element1provided to the quartz crystal oscillator30is provided with the intermediate weight section4formed to have an arm width W1larger (thicker) than the arm width W of the vibrating arm section3and smaller (thinner) than the arm width W2of the tip weight section5, thereby making the intermediate weight section4follow the vibration (the amplitude) of the vibrating arm section3. Further, the quartz crystal vibrator element1is provided with the tip weight section5formed to have an arm width W2larger (thicker) than the arm width W1of the intermediate weight section4, thereby making the tip weight section5follow the vibration (the amplitude) of the vibrating arm section3and the intermediate weight section4. Thus, the quartz crystal oscillator30with the vibration of the vibrating arm section3and the vibrational frequency of the quartz crystal vibrator element1stabilized can be obtained.

Further, by gradually increasing the arm width of the first widening section7from the arm width W of the vibrating arm section3to the arm width W1of the intermediate weight section4in accordance with the difference between the arm width W of the vibrating arm section3and the arm width W1of the intermediate weight section4, the quartz crystal vibrator element1suppresses the asymmetry property of the etching due to the anisotropy of the quartz crystal as the piezoelectric material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the vibrating arm section3and the intermediate weight section4. Thus, the balance can be maintained between the two vibrating arm sections3, and thus the quartz crystal oscillator30, which stabilizes the vibration characteristics of the quartz crystal vibrator element1, can be obtained.

Further, by gradually increasing the arm width of the second widening section8from the arm width W1of the intermediate weight section4to the arm width W2of the tip weight section5in accordance with the difference between the arm width W1of the intermediate weight section4and the arm width W2of the tip weight section5, the quartz crystal vibrator element1suppresses the asymmetry property of the etching due to the anisotropy of the quartz crystal as the piezoelectric material. Therefore, it is possible to provide the symmetry property with respect to the vibration direction (the amplitude direction) between the intermediate weight section4and the tip weight section5. Thus, the highly accurate balance can be maintained between the two vibrating arm sections3, thereby making it possible to obtain the quartz crystal oscillator30, which further stabilizes the vibration characteristics of the quartz crystal vibrator element1.

Electronic Apparatus

The quartz crystal oscillator30according to the embodiment described above can be applied to various types of electronic apparatus, and the electronic apparatuses become highly reliable.FIGS. 5 and 6show a cellular phone as an example of the electronic apparatus according to the invention.FIG. 5is a perspective view showing a schematic appearance of the cellular phone, andFIG. 6is a circuit block diagram for explaining a circuit configuration of the cellular phone. The cellular phone100will be explained as an example of using the quartz crystal oscillator30using the quartz crystal vibrator element1(FIGS. 1A through 1C), and regarding the configuration and the operation of the quartz crystal oscillator30, the same reference numerals are used, and therefore, the explanation therefor will be omitted.

As shown inFIG. 5, the cellular phone100is provided with a liquid crystal display (LCD)101as the display section, keys102as an input section of the numerical characters and so on, a microphone103, a speaker111, and so on. Further, as shown inFIG. 6, in the case of performing the transmission in the cellular phone100, when the user inputs his or her voice to the microphone103, it results that the signal passes through the pulse width modulation/coding block104and the modulator/demodulator block105, and is then transmitted from the antenna108via a transmitter106and an antenna switch107.

Incidentally, a signal transmitted from a cellular phone of another person is received by the antenna108, and then input from a receiver110to the modulator/demodulator block105via the antenna switch107and a receive filter109. Further, it is arranged that the signal modulated or demodulated passes through the pulse width modulation/coding block104, and is then output from the speaker111as a voice. Further, there is provided a controller112for controlling the antenna switch107, the modulator/demodulator block105, and so on.

The controller112also controls the LCD101as the display section, the keys102as the input section for the numerical characters and so on, and further a RAM113, a ROM114, and so on besides the constituents described above, and is therefore required to be highly accurate. Further, improvement in the reliability of the cellular phone100is also required, and as the device satisfying such a requirement, the quartz crystal oscillator30having the quartz crystal vibrator element1with the vibrational frequency stabilized is used. It should be noted that although the cellular phone100is also provided with a temperature compensated crystal oscillator115, a receiver dedicated synthesizer116, a transmitter dedicated synthesizer117, and so on as additional constituent blocks, the explanation therefor will be omitted here.

Further, as the electronic device equipped with the quartz crystal oscillator30according to the invention, there can also be cited a personal computer (a mobile personal computer)200shown inFIG. 7. The personal computer200is provided with a display section201, an input key section202, and so on, and the quartz crystal oscillator30with the stabilized vibrational frequency is used as the reference clock for electrical control therefor.

The quartz crystal vibrator element1of the quartz crystal oscillator30used in the cellular phone100or the personal computer200described above has the first widening section7, the intermediate weight section4, the second widening section8, and the tip weight section5in the tip portion of the vibrating arm section3, and is capable of keeping the stable vibrational frequency due to these constituents. Therefore, it is possible for the cellular phone100and the personal computer200to achieve a high reliability.

It should be noted that, as the electronic apparatus provided with the quartz crystal oscillator30according to the invention, there can be cited in addition to the devices described above, for example, a digital still camera, an inkjet ejection device (e.g., an inkjet printer), a laptop personal computer, a television set, a video camera, a video cassette recorder, a car navigation system, a pager, a personal digital assistance (including one with communication function), an electronic dictionary, an electric calculator, a computerized game machine, a word processor, a workstation, a video phone, a security video monitor, a pair of electronic binoculars, a POS terminal, a medical device (e.g., an electronic thermometer, an electronic manometer, an electronic blood sugar meter, an electrocardiogram measurement instrument, an ultrasonograph, and an electronic endoscope), a fish detector, various types of measurement instruments, various types of gauges (e.g., gauges for a vehicle, an aircraft, or a ship), and a flight simulator.

Although the electronic apparatuses according to the invention are described based on the embodiments shown in the accompanying drawings as described above, the present invention is not limited to these embodiments, but the configuration of each of the components can be replaced with one having an identical function and any configuration. Further, it is possible to add any other constituents to the invention. For example, although in the embodiments described above the case in which the quartz crystal vibrator element1has a pair of vibrating arm sections3as the vibrating sections is explained as an example, the number of vibrating arm sections3can also be three or larger. Further, a beam type vibrator element composed of one vibrating arm alone having the base portion to be the fixed end can also be adopted.

Further, the quartz crystal vibrator element1explained in the embodiments described above can also be applied to a gyro sensor or the like besides the oscillator such as a voltage controlled crystal oscillator (VCXO), a temperature compensated crystal oscillator (TCXO), and an oven controlled crystal oscillator (OCXO).

Further, in the quartz crystal vibrator element1, modifications, improvements, and so on within the range where at least a part of problems described above can be solved can be included in the embodiment described above.

For example, although in the explanation it is assumed that the quartz crystal vibrator element1is provided with the first widening section7and the second widening section8, the configuration is not limited thereto, but it is also possible to assume that the first widening section7is not provided between the vibrating arm section3and the intermediate weight section4, or the second widening section8is not provided between the intermediate section4and the tip weight section5, which can arbitrarily be selected.

Further, although in the explanation, it is assumed that the quartz crystal vibrator element1is provided with the coupling section11, the support section12, and the cut sections13, the configuration is not limited thereto, but the configuration without the support section12can also be adopted. On this occasion, the mounting electrodes are provided to either one of the coupling section11and the base portion2, and the quartz crystal vibrator element1is fixed to the conductive fixing sections25with the electrically conductive adhesive28, and is electrically connected thereto. Alternatively, the configuration without the support section12, the coupling section11, and the cut sections13can also be adopted. On this occasion, the mounting electrodes are provided to the base portion2, and the quartz crystal vibrator element1is fixed to the conductive fixing sections25with the electrically conductive adhesive28, and is electrically connected thereto.

Further, although the thickness dimension (in the vertical direction in the drawing) of the quartz crystal vibrator element1is constant in the illustration ofFIGS. 3A,3B and4, the configuration is not limited thereto, but the base portion2, the intermediate weight section4, the tip weight section5, and so on constituting the quartz crystal vibrator element1can be different in thickness dimension from the vibrating arm section3. It should be noted that it is preferable that the vibrating arm sections, the intermediate weight sections, the tip weight sections, and so on constituting the quartz crystal vibrator element denoted with the same names and the same reference numerals do not have the respective thickness dimensions different from each other.

Further, although in the explanation it is assumed that the quartz crystal vibrator element1has two weight sections, namely the intermediate weight section4and the tip weight section5, the configuration is not limited thereto, but it is also possible for the quartz crystal vibrator element1to have an Nthweight section (N is an integer equal to or larger than 3) with an arm width W(N) (N is an integer equal to or larger than 3) larger than the arm width W1of the intermediate weight section and smaller than the arm width W2of the tip weight section disposed between the intermediate weight section4and the tip weight section5. Specifically, the relationship between the arm width W(N) (N is an integer equal to or larger than 3) of the Nthweight section, the arm width W1, and the arm width W2can be as follows.

Alternatively, it is also possible to have the Nthweight section with the arm width W(N) larger than the arm width W of the vibrating arm section3and smaller than the arm width W1of the intermediate weight section4disposed between the vibrating arm section3and the intermediate weight section4. Specifically, the relationship between the arm width W(N) (N is an integer equal to or larger than 3) of the Nthweight section, the arm width W1, and the arm width W2can be as follows.

Still further, it is also possible to have the Nthweight section with the arm width W (N) larger than the arm width W2of the tip weight section5on the tip side of the tip weight section5. Specifically, the relationship between the arm width W(N) (N is an integer equal to or larger than 3) of the Nthweight section, the arm width W1, and the arm width W2can be as follows.

Further, the package21for housing the quartz crystal vibrator element1is not limited to the embodiment described above, but can be of a so-called cylinder type made of metal such as iron (Fe), cobalt (Co), or nickel (Ni), or an alloy containing a combination of these metals. The electrically conductive adhesive28can be solder.

Further, the material of the vibrator element is not limited to the quartz crystal, but can be a piezoelectric substance such as lead zirconium titanate (PZT), zinc oxide (ZnO), aluminum nitride (AlN), lithium tantalate (LiTaO3), lithium tetraborate (Li2B4O7), lithium niobate (LiNbO3), or a semiconductor such as silicon as a non-piezoelectric material.

The entire disclosures of Japanese Patent Application Nos.: 2010-060326 filed Mar. 17, 2010, and 2010-277758 filed Dec. 14, 2010 are expressly incorporated by reference herein.