JP4411496B6 - Portable device equipped with crystal oscillator and manufacturing method thereof - Google Patents

Description

  The present invention relates to a crystal resonator including a vibrating arm and a base that vibrate in a bending mode, a crystal unit including the resonator, a case, and a lid, an amplifier circuit, and a feedback circuit. In particular, crystal units, crystal units, and crystal oscillators that are ideal as reference signal sources for information and communication equipment that are highly demanded for miniaturization, high accuracy, impact resistance, and low cost. New shapes, new electrode configurations, and optimal dimensions. The present invention relates to a crystal unit composed of an ultra-compact bent crystal resonator having a crystal oscillator and a crystal oscillator whose oscillation frequency of fundamental mode vibration is an output signal.

A conventional bent crystal resonator includes a tuning fork arm and a tuning fork base, and electrodes are disposed on the upper and lower surfaces and side surfaces of the tuning fork arm. In addition, the conventional crystal unit is composed of a tuning fork-type bending crystal unit composed of a tuning fork arm and a tuning fork base formed integrally with a case and a lid. Further, the crystal oscillator includes an amplifier, a capacitor, a resistor, and upper and lower surfaces of the tuning fork arm. A crystal oscillator composed of a conventional tuning-fork type bent crystal resonator having electrodes arranged on the side surfaces is well known. A conventional tuning fork-type bending crystal resonator that is frequently used is composed of two tuning fork arms and a tuning fork base, and the resonance frequency of the transducer is proportional to the arm width W of the tuning fork and is the square of the length of the tuning fork arm. Inversely proportional. Therefore, it is necessary to reduce the arm width W in order to reduce the size. However, reducing the arm width W, a problem that the equivalent series resistance R ₁ becomes larger it had been left. Further, downsizing of the crystal unit and the crystal oscillator of the conventional example including the tuning-fork type bent crystal resonator has been left as a problem at the same time.

The reason why R ₁ increases is that the equivalent series resistance R ₁ decreases as the electric field component Ex of the electrode disposed on the tuning fork arm in the direction of the electric axis (x-axis) of the crystal increases, and the quality factor Q value increases. . However, in the tuning fork-type bent quartz crystal resonator that has been conventionally used, electrodes are arranged on the upper and lower surfaces and side surfaces of each tuning fork arm. For this reason, the electric field does not work linearly, and when the tuning fork type quartz crystal resonator is miniaturized, the electric field component Ex is reduced, the equivalent series resistance R ₁ is increased, and the quality factor Q value is decreased. At the same time, there remains a problem of obtaining a bent crystal resonator that is highly accurate as a time reference, that is, has high frequency stability and suppresses second harmonic mode vibration. As a method for solving the above-mentioned problem, for example, JP-A-56-65517 discloses a groove on a tuning fork arm, and discloses a groove structure and an electrode structure. However, the configuration of the groove, full Iga of merit related to the relationship and the frequency stability of the equivalent series resistance R ₂ of the equivalent series resistance R ₁ of the second harmonic mode vibration in the vibration mode and fundamental mode vibration and dimension M is not disclosed at all. At the same time, when the vibrator having the groove is connected to a conventional circuit to form a crystal oscillation circuit, the output signal of the fundamental mode vibration is affected by the impact or vibration, and the output signal is the second harmonic mode vibration. Problems such as frequency change and detection have occurred. Furthermore, in order to reduce the current consumption of the crystal oscillator, reducing the load capacitance C _L, liable to vibration second harmonic mode, problems such as not to obtain the output frequency of the fundamental mode oscillation is left It was. Furthermore, since the vibrator is fixed to the fixed portion of the container at the tuning fork base, there is a problem that the length dimension of the tuning fork base cannot be reduced, and a small tuning fork-type bent quartz crystal having a short overall length cannot be obtained.
JP-A-56-65517 JP 2000-223992 A International Publication No. 00/44092 JP2003-163568

Because of this, even if the crystal unit is subjected to shock or vibration, a bent crystal unit that vibrates in the fundamental wave mode that suppresses second harmonic mode vibrations that are not affected by the impact and vibration, and a crystal unit including the same And a crystal oscillator was desired. Furthermore, short length of the crystal resonator to vibrate in the fundamental mode, i.e., a short ultra-small overall length, a small equivalent series resistance R _1, the new shape, such as the quality factor Q value increases, the electric machine Ultra-compact bent crystal unit with groove structure and electrode configuration with good conversion efficiency, crystal unit equipped with it, and output signal with oscillation frequency of fundamental mode vibration with the crystal unit and high frequency stability An ultra-small crystal oscillator having high performance (high time accuracy) has been desired. At the same time, a crystal oscillator with low current consumption and short rise time has been desired.

  An object of the present invention is to provide a bent crystal resonator that vibrates in a bending mode that advantageously solves the conventional problems by the following method, a crystal unit including the same, and a crystal oscillator.

That is, the first aspect of the portable device equipped with the crystal oscillator of the present invention is a crystal oscillator including an amplifier circuit configured to include at least an amplifier, and a feedback circuit configured to include at least a crystal resonator and a capacitor. In a portable device including a crystal oscillator configured with a circuit, the crystal resonator includes a base, a first vibrating arm connected to the base, and a second vibrating arm, and a tuning fork-shaped bent crystal. In the vibrator, each of the first vibrating arm and the second vibrating arm has an upper surface, a lower surface, and a side surface, the base is connected to one frame through one connection portion, and the other connection The one frame and the other frame are connected to the other frame via a portion, and the first vibrating arm and the second vibrating arm have a common direction outside the tuning fork different from the tuning fork fork side. Formed to extend to The one frame and the other frame are opposite to each other with respect to the base, and a groove is formed on each of the upper surface and the lower surface of each of the first vibrating arm and the second vibrating arm. In addition, each of the first vibrating arm and the second vibrating arm includes a distal end portion which is a free end and an end portion which is opposite to the distal end portion and connected to the base portion, and the distal end portion And two different widths between the one end and one of the two different widths is located on the tip side and the other one of the two different widths. The width is smaller than the width of the first vibration arm and the second vibration arm which are located on the one end side opposite to the front end side and smaller than the width located on the front end side. The grooves formed on each of the upper surface and the lower surface of each of the first vibration arm and the second vibration arm Formed on each of the upper and lower surfaces of the resonating arm having the width located on the one end side, and the one frame and the other frame are fixed to a fixing portion of the case, Is a portable device equipped with a crystal oscillator joined to a lid via a joining member.
A second aspect of the portable device equipped with a crystal oscillator of the present invention, in the first aspect, of the bent crystal oscillator Figa of merit M ₁ of the fundamental wave mode vibration second harmonic mode vibration Fuigaobu have a merit M _2, the fundamental mode vibration of the full Iga of merit M ₁ is a portable device provided with a full Iga of merit M ₂ is larger than the crystal oscillator of the second harmonic mode vibration.
According to a third aspect of the portable device in which the crystal oscillator of the present invention is mounted, in the first aspect or the second aspect, the amplifier has an absolute value of a negative resistance in a fundamental mode vibration of the bent crystal resonator. RL ₁ |, and the fundamental mode vibration of the bent quartz crystal resonator has an equivalent series resistance R ₁ and an equivalent inductance L _m1, and the absolute value | −RL ₁ | of the negative resistance and the equivalent series resistance between R ₁ and the equivalent inductance _{L m1, | -RL 1 | -R} 1 ▲ ≧ ▼ a portable apparatus equipped with a crystal oscillator that includes the relationship _{2L m1.}
A first aspect of a method for manufacturing a portable device equipped with a crystal oscillator of the present invention is a crystal including an amplifier circuit configured to include at least an amplifier, and a feedback circuit configured to include at least a crystal resonator and a capacitor. In a method for manufacturing a portable device including a crystal oscillator configured to include an oscillation circuit, the crystal resonator includes a base, and a tuning fork configured to include a first vibrating arm and a second vibrating arm connected to the base. A bent crystal resonator having a shape, wherein each of the first vibrating arm and the second vibrating arm has an upper surface, a lower surface, and a side surface, and the base portion is connected to one frame via one connection portion; and The first vibrating arm and the second vibrating arm are connected to the other frame through the other connecting portion, and the one frame and the other frame are outside the tuning fork different from the tuning fork fork side. And extend in the same direction The one frame and the other frame are opposite to each other with respect to the base, and a groove is formed on each of the upper surface and the lower surface of each of the first vibrating arm and the second vibrating arm. Each of the first vibrating arm and the second vibrating arm is provided with a distal end portion that is a free end and an end portion that is opposite to the distal end portion and connected to the base portion, and , Having two different widths between the tip portion and the one end portion, wherein one of the two different widths is located on a side of the tip portion, and is within the two different widths. The other one width is located on the one end side opposite to the tip end side and smaller than the width located on the tip end side, and the first vibrating arm and the The groove formed on each of the upper surface and the lower surface of each of the second vibrating arms includes the first vibrating arm and the 2 formed on the upper surface and the lower surface of the vibrating arm having the width located on the one end side of each of the vibrating arms, and the one frame and the other frame are fixed to the fixing portion of the case It is a method for manufacturing a portable device equipped with a crystal oscillator that is fixed, the case is bonded to a lid via a bonding member, and includes a step of adjusting the frequency of the bent crystal resonator.
According to a second aspect of the method for manufacturing a portable device equipped with the crystal oscillator of the present invention, in the first aspect, the tuning fork-shaped bent crystal resonator includes a tuning fork arm including a first vibrating arm and a second vibrating arm. In addition, a tuning fork-shaped bent quartz crystal resonator having the tuning fork arm is formed in a quartz wafer so that the frequency is higher than 32.768 kHz, and after the formation, the frequency is bent so that the frequency is lower than 32.768 kHz. A weight is attached to the tuning fork arm of the crystal resonator, and after the attachment, a bent crystal resonator having a frequency lower than 32.768 kHz is fixed to a fixing portion of a container to be stored, and the tuning fork arm is provided after the fixing. The output frequency of the output signal of the crystal oscillation circuit configured with the bent crystal resonator is within the range of −100 ppm to +100 ppm with respect to 32.768 kHz. By removing the serial tuning fork arm of the weight is a manufacturing method for a mobile device equipped with a crystal oscillator frequency adjustment.
According to a third aspect of the method for manufacturing a portable device equipped with the crystal oscillator of the present invention, in the first aspect or the second aspect, the bending crystal resonator has a fundamental mode vibration capacity ratio r ₁ and a quality factor Q. ₁ , frequency stability factor S ₁ , second harmonic mode vibration capacity ratio r ₂ , quality factor Q ₂ and frequency stability factor S ₂ , and S ₁ = r ₁ / 2Q ₁ ² and S ₂ = r as defined ^₂ / _{2Q 2 2, S 1} is a manufacturing method of a portable device equipped with _{S 2} smaller crystal oscillator.

  As described above, the present invention provides a bent crystal resonator that vibrates in a bending mode, a crystal unit and a crystal oscillator including the same, and improves the shape of the base, the groove configuration, and the electrode arrangement of the bent crystal resonator. By this, a bent crystal resonator with a short overall length can be obtained, and a crystal that outputs an oscillation frequency that vibrates with fundamental wave mode vibration by suppressing the second harmonic mode vibration by showing the relationship between the amplifier circuit and the feedback circuit. You can get an oscillator.

In addition, a groove is provided in the center part including (including) the neutral line of the vibrating arm, or a groove is provided on both sides of the neutral line leaving all or part of the neutral line, and electrodes are disposed, and the groove by optimizing the dimensions, low equivalent series resistance R _1, Q value is high, micro bending crystal oscillator that oscillates at a good bending modes electromechanical conversion efficiency can be obtained. At the same time, the load capacity of the feedback circuit can be reduced. As a result, a crystal oscillator with low current consumption can be obtained.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

Example 1 bent crystal resonator

  FIG. 1 is a plan view of a bent crystal resonator 10 that vibrates in a bending mode according to a first embodiment of the present invention. Also, x, y, and z are the crystal electrical axis, mechanical axis, and optical axis, respectively. The shape of the vibrator of the present embodiment is a tuning fork shape, and the bent quartz crystal vibrator 10 is composed of a vibrating arm 20, a vibrating arm 31, and a base 40, and one end of the vibrating arm 20 and the vibrating arm 31 is connected to the base 40. Yes. The vibrating arm 20 and the vibrating arm 31 have an upper surface, a lower surface, and a side surface, respectively. Further, the groove 21 is provided on the upper surface of the vibrating arm 20 with the neutral line 41 interposed therebetween, that is, so as to include the neutral line 41, and the groove 27 is provided on the upper surface of the vibrating arm 31 similarly to the vibrating arm 20. It has been. The angle θ is a rotation angle around the x axis, and is usually selected in the range of 0 to 10 °. Also, grooves are provided on the lower surfaces of the vibrating arms 20 and 31 in the same manner as the upper surface (see FIG. 2). Specifically, the groove 21 is provided so as to sandwich the neutral line 41 of the vibrating arm 20. The other vibrating arm 31 is also provided with a groove 27 so as to sandwich the neutral line 42.

  Further, the base 40 is connected to the frame 36 through one connecting portion 34 and is connected to the frame 37 through the other connecting portion 35. The vibrator of the present embodiment is fixed to a fixing portion of a container in which the frames 36 and 37 are accommodated with a conductive adhesive or solder. In addition, electrodes 25 and 26 are disposed on the side surface of the vibrating arm 20, and an electrode 23 is disposed in the groove 21, and extends to the frame 36 through the connection portion 34. In addition, electrodes 32 and 33 are disposed on the side surface of the vibrating arm 31, and an electrode 29 is disposed in the groove 27, and extends to the frame 37 through the connection portion 35.

Furthermore, assuming that the partial widths W ₁ and W ₃ of the vibrating arms and the groove width W ₂ , the arm widths W of the vibrating arms 20 and 31 are given by W = W ₁ + W ₂ + W ₃ , and are usually W ₁ and W ₃ . A part or all of them are formed such that W ₁ ▲ ≧ ▼ W ₃ or W ₁ <W ₃ . Further, the groove width W ₂ is formed under the conditions satisfying W ₂ ≧ W ₁ and W ₃ . More specifically, in this embodiment, the ratio (W ₂ / W) between the groove width W ₂ and the vibrating arm width W is larger than 0.35 and smaller than 1, preferably 0.35. ˜0.95, and as shown in FIG. 2, the ratio (t ₁ / t) between the groove thickness t ₁ and the vibrating arm thickness t (t ₁ / t) is preferably less than 0.79. Grooves are formed on the vibrating (tuning fork) arm so as to be 0.79. By forming in this way, the moment with the neutral lines 41 and 42 of the vibrating arm as the base point is increased. That is, since the electro-mechanical conversion efficiency is improved, a small equivalent series resistance R _1, a high Q value, moreover, it is possible to obtain a small flexural crystal oscillator capacity ratio.

On the other hand, although not shown, the groove 21 and the groove 27 have a groove length L ₀ , and the vibrating arm has an arm length L. Therefore, in order to obtain a vibrator having a small R ₁ , L ₀ / L has a value of 0.4 to 0.8. Here, when the electrode disposed in the groove is disposed in a part of the groove, L ₀ is the length L _d of the electrode in the groove. Furthermore, the total length L _t of the bent quartz resonator 10 of the tuning fork is determined from such as the size of the frequency or container required. In this embodiment, L _t is 2.8 mm or less, preferably 2.1 mm or less. In order to further reduce the size, the distance is in the range of 1.02 mm to 1.95 mm. The overall width _{W 5 (= 2W + W 4} ) of the vibrating arm is below 0.43 mm, preferably in the range of 0.15Mm～0.36Mm. Further, in this embodiment, the width of (the tuning fork) base is given by W _H, has a relationship of W _H ▲ ≧ ▼ W _5. And _WH is 0.55 mm or less, Preferably, it exists in the range of 0.15 mm-0.53 mm. The frame width W ₆ is 0.45 mm or less, the frame length L ₃ is 2.1 mm or less, and preferably L ₃ is 0.3 mm to 1.85 mm in order to reduce vibration leakage. Is in range. The width _{W S} of the connecting portion is below 0.41 mm, the length _{L 2} length is minimum of the connecting portion is in the range of 0.04Mm～0.5Mm. Furthermore, in order to obtain a good tuning fork type flexural quartz crystal resonator vibrating at the fundamental mode, a close relationship exists between the length L ₀ and the total length L _t of the groove.

That is, the ratio (L ₀ / L _t ) between the length L _{0 of the} groove provided in the vibrating arms 20 and 31 and the total length L _t of the tuning fork-shaped bent quartz crystal resonator is 0.23 to 0.88. The length of the groove is provided. In particular, L ₀ is 1.45 mm or less, preferably L ₀ is in the range of 0.48 mm to 1.29 mm. Further, L ₀ may extend to the base (the length L _K of the groove on the base). The reason for forming in this way is that, in particular, it is possible to suppress the second harmonic vibration, which is an unnecessary vibration, and to improve the frequency stability of the fundamental mode vibration. Therefore, it is possible to realize a good bent crystal resonator that easily vibrates in the fundamental wave mode. If described in detail, the equivalent series resistance R ₁ of the bending quartz oscillator tuning fork vibrating at the fundamental mode is smaller than the equivalent series resistance R ₂ at the second harmonic mode vibration. That is, R ₁ <R _{2 is} satisfied, and in the crystal oscillator including the amplifier (CMOS inverter), the capacitor, the resistor, and the tuning-fork-shaped bent crystal resonator according to the present embodiment, the resonator easily oscillates in the fundamental wave mode. A crystal oscillator can be realized. That is, the oscillation frequency of the fundamental mode vibration is obtained as an output signal. Further, the groove length L ₀ may be divided in the length direction of the vibrating arm, and at least one of them may satisfy the side ratio (L ₀ / L _t ) or may be divided. The length of the added groove in the length direction of the formed groove should satisfy the side ratio (L ₀ / L _t ).

Further, in this embodiment, the base 40 is the entire length L ₁ and width _WH of the vibrator 10 in FIG. 1, and the vibrating arm 20 and the vibrating arm 31 are the vibrator 10 in FIG. there is a whole upper portion from the portion of the length L ₁ of. In the present embodiment, the tuning fork fork has a U-shape, but the present invention is not limited to the above shape, and the tuning fork fork may have a rectangular shape. In this case as well, as in the U-shaped shape, the dimensional relationship between the vibrating arm and the base is the same as the above relationship. The groove length L _{0 referred} to in the present invention means that the ratio (W ₂ / W) of the groove width W ₂ to the vibrating arm width W is larger than 0.35, smaller than 1, and the groove thickness t. ₁ is a length of a groove formed so that a ratio (t ₁ / t) of ₁ and the thickness t of the vibrating arm is smaller than 0.79.

In other words, at least one groove is provided in the longitudinal direction on the upper and lower surfaces of the vibrating arm including the neutral line, electrodes are disposed on both side surfaces of the groove, and the electrodes on the side surfaces of the groove and the electrodes are opposed to the electrodes. vibrating arms and the side electrodes are configured such that different poles each other, at least one of groove width W ₂ and the vibration arm width of said each at least one groove as the moment of inertia generated in the vibration arm is increased to The ratio (W ₂ / W) to W is larger than 0.35 and smaller than ₁ , and the ratio (t ₁ / t) between the thickness t _{1 of the} groove and the thickness t of the vibrating arm is smaller than 0.79. A groove is formed so as to be.

As an example, the vibrating arm includes at least a first vibrating arm and a second vibrating arm, and the first vibrating arm, the second vibrating arm, and the base are integrally formed by an etching method, Grooves are provided on the upper and lower surfaces of the vibrating arm and the second vibrating arm, respectively, in the thickness direction, and the groove is located above the central portion in the width direction across the neutral line of the first vibrating arm and the second vibrating arm. each one of the grooves is provided on the lower surface, each groove width W ₂ of equal to or partial width W _1, W _3, or partial width W _1, W ₃ are formed so than larger, and, each of the grooves The electrode of the groove of the first vibrating arm and the electrode of the groove of the second vibrating arm are arranged with different polarities, and the electrode on the side surface of the vibrating arm arranged opposite to the electrode of the groove Two electrode terminals having different polarities are formed, and one of the two electrode terminals is formed in a groove on the upper and lower surfaces of the first vibrating arm. The electrode arranged on both sides of the second vibrating arm and the electrode arranged on the upper and lower grooves and the electrode arranged on both sides are connected to each other. The electrode terminal is composed of electrodes arranged on both side surfaces of the first vibrating arm and electrodes arranged in grooves on the upper and lower surfaces of the second vibrating arm, and the electrodes arranged on both side surfaces and grooves on the upper and lower surfaces. The arranged electrodes are connected.

Further, the distance between the vibrating arms of the present embodiment is given by W ₄ , and the distance W ₄ and the groove width W ₂ are configured to satisfy W ₄ ▲ ≧ ▼ W ₂ , and the distance W ₄ is 0.05 mm to 0 mm. .37 mm and the groove width W ₂ has a value of 0.018 mm to 0.12 mm. Preferably, W ₂ = 0.02 mm to 0.069 mm. The reason for this configuration is an ultra-compact bent quartz crystal resonator, and the tuning fork shape and the groove of the vibrating arm can be formed separately (separate steps) using photolithography technology. The frequency stability can be made higher than the frequency stability of the second harmonic mode vibration. In this case, a quartz wafer having a thickness t of usually 0.05 mm to 0.15 mm is used. However, the present invention is not limited to this, and a quartz wafer thicker than 0.15 mm may be used.

More specifically, the Figer of Merit M _i representing the inductivity, electromechanical conversion efficiency, and quality factor of the bent quartz resonator is the ratio of the quality factor Q _i value to the capacity ratio r _i (Q _i / r _i ). defined by (i = 1 when the fundamental wave vibration, the second harmonic oscillation when i = 2), the series resonance that depends on the parallel capacitance and mechanical series resonance frequency f _s that is independent of the parallel capacitance of the flexural crystal oscillator the frequency difference Δf of frequency f _r is inversely proportional to the full Iga of merit M _i, Δf becomes smaller as the value M _i is large. Therefore, as M _i is large, the resonance frequency of the bending crystal oscillator does not influenced by the parallel capacitance, the frequency stability of a flexural quartz crystal resonator is improved. That is, a bent crystal resonator with high time accuracy can be obtained.

More specifically, the configuration of the tuning fork shape, the groove, and its dimensions makes the fibre-of-merit M ₁ of the fundamental mode vibration larger than the fibre-of-merit M ₂ of the second harmonic mode vibration. That is, M ₁ > M ₂ is satisfied. As an example, when the reference frequency of the fundamental wave mode vibration of the tuning fork shape is 32.768 kHz, W ₂ /W=0.5, _{t 1} /t=0.34, L ₀ / L _t = 0.48 However, M ₁ and M ₂ of the tuning fork-shaped bent quartz crystal resonator satisfy M ₁ > 60 and M ₂ <30, respectively. That is, (a small equivalent series resistance R ₁₎ Good high inductive electromechanical conversion efficiency, can be obtained flexural quartz oscillator that vibrates at a large fundamental mode of the quality factor. As a result, the frequency stability of the fundamental wave mode vibration becomes better than the frequency stability of the second harmonic mode vibration, and the second harmonic mode vibration can be suppressed.

Further, the base 40 of the bent quartz crystal resonator 10 of the present embodiment is connected to the frames 36 and 37 via the connection portions 34 and 35. Further, the length of the connecting portion 34, 35 have respective _{L 2,} the length dimension and width dimension of the frame 37 has a _{L 3} and _{W 6,} respectively. Each dimension is formed so as to satisfy the relationship of L ₃ ▲ ≧ ▼ L ₂ , L ₁ ▲ ≧ ▼ L ₂ , or L ₁ <L ₂ . Further, L ₁ has a dimension of less than 0.5 mm in order to reduce the size. Preferably, it exists in the range of 0.015 mm-0.45 mm. At the same time, the difference between _{L 1} and _{L 2, i.e.,} L 1 -L ₂ is in the range of -0.1Mm～0.32Mm. In particular, when W _H > W ₅ , the length L ₄ is in the range of 0.012 mm to 0.38 mm. In this embodiment, the frame 36 and the frame 37 are not connected, but both frames may be connected so as to pass near the tip of the tuning fork. That is, the present invention also includes the shape. In this embodiment, the frame is provided from the side surface of the base portion via the connecting portion. However, the present invention is not limited to this, and the frame protrudes from the base portion between the vibrating arms (tuning fork arms). A frame may be provided. Further, in this embodiment, the groove is provided in the vibrating arm and the electrode is disposed therein. However, the present invention is not limited to this, and the groove is not provided (planar), and the upper surface of the vibrating arm is provided. You may arrange | position the electrode with the same polarity as the electrode of each groove | channel on the lower surface. Needless to say, these can also be applied to the bent crystal resonator of the embodiment described below.

  FIG. 2 is a cross-sectional view taken along the line AA ′ of the vibrating arms 20 and 31 of the bent crystal resonator 10 of FIG. FIG. 2 details the cross-sectional shape and electrode arrangement of the vibrating arms 20 and 31 of the crystal resonator of FIG. The vibrating arm 20 is provided with grooves 21 and 22. Similarly, the vibrating arm 31 is provided with grooves 27 and 28. Furthermore, electrodes 23 and 24 having the same polarity are disposed in the grooves 21 and 22, and electrodes 29 and 30 having the same polarity are disposed in the grooves 27 and 28. In addition, electrodes 25 and 26 having the same polarity are disposed on the side surface of the vibrating arm 20, and electrodes 32 and 33 having the same polarity are disposed on the side surface of the vibrating arm 31. Specifically, an electrode is disposed on the side surface of the groove, and a two-electrode terminal C-C ′ is configured in which electrodes having different polarities are disposed on the side surface of the vibrating arm. That is, one electrode terminal is configured and connected from electrodes 25, 26, 29, and 30. The other one electrode terminal is constituted and connected by electrodes 23, 24, 32, and 33. More specifically, the counter electrodes arranged to oppose the electrodes 25, 26, 32, 33 arranged on both side surfaces of the first vibrating arm 20 and on both side surfaces of the second vibrating arm 31 are the first vibrating arm and the first vibrating arm. A part of each of the electrodes on both side surfaces of the second vibrating arm is arranged so as to face each other.

That is, the groove electrode that opposes the z-axis (thickness) direction has the same polarity, and the electrode that opposes the x-axis direction generally has a different polarity. Specifically, the electric field generated perpendicularly to the groove electrode does not exist in the thickness method between the groove electrode opposed to the electrode disposed in the groove provided in the thickness direction. An electrode is disposed on the surface. Now, when a DC voltage is applied between the two electrode terminals C-C '(a positive electrode at the C terminal and a negative electrode at the C' terminal), the electric field Ex works as shown by the arrow in FIG. The electric field Ex is drawn perpendicularly to the electrode by the electrodes arranged opposite to the side surface of the vibrating arm and the side surface in the groove, that is, linearly drawn, so that the electric field Ex is increased, resulting in vibration (tuning fork). At the same time, distortion occurs in the length direction of the arm, and the direction of distortion occurs oppositely on the inside and outside of the vibrating (tuning fork) arm with respect to the neutral line, and the first vibrating (tuning fork) arm and the second vibration The direction of distortion generated inside the tuning fork is the same with respect to the neutral line of the (tuning fork) arm, and occurs outside the tuning fork with respect to the neutral line of the first vibrating (tuning fork) arm and the second vibrating (tuning fork) arm. The strain direction is the same, and the inner strain and the outer strain are generated in opposite directions. Therefore, by applying an alternating voltage between the two-electrode terminals C-C ′, the vibrating (tuning fork) arm vibrates in the opposite phase, improving the resonance characteristics and increasing the amount of distortion generated. Therefore, even when the tuning fork-shaped bent quartz crystal is reduced in size, a tuning fork-shaped bent quartz crystal that vibrates in a bending mode having a small equivalent series resistance R ₁ and a high quality factor Q value can be obtained.

The vibration (tuning fork) arm of the bent quartz resonator 10 has a thickness t, groove has a thickness t _1. The thickness t ₁ here refers to the thickness of the deepest part of the groove. The reason for this is that the etching speed varies depending on the direction of each crystal axis in the chemical etching method because quartz is an anisotropic material. Therefore, the chemical etching method causes variations in the groove depth, and it is extremely difficult to process the uniform shape shown in FIG. In the present embodiment, the ratio (t ₁ / t) between the groove thickness t ₁ and the vibration (tuning fork) arm thickness t is preferably 0.01 to 0.79 so as to be smaller than 0.79. Thus, a groove is formed in the vibrating arm. By forming in this way, the electric field Ex between the groove side surface electrode of the vibrating arm and the side electrode opposed thereto increases. That is, it is possible to obtain a bent crystal resonator having a large moment with the neutral line as a base point and high electromechanical conversion efficiency. That is, a tuning fork-shaped bent quartz crystal resonator with a small capacity ratio can be obtained.

Bent crystal resonator of Example 2

  FIG. 3 is a plan view of a bent crystal resonator 50 that vibrates in the bending mode according to the second embodiment of the present invention. The vibrator 50 includes vibrating arms 60 and 71 and a base portion 80, and a side surface of the base portion 80 is connected to a frame 77 through a connection portion 75. That is, the frame 77 is connected to only one side of the side surface of the base 80 via the connection portion 75. Further, the vibrating arm 60 is provided with a groove 61 with a neutral line 81 interposed therebetween, and an electrode 63 is disposed in the groove 61. Electrodes 65 and 66 are disposed on the side surface of the vibrating arm 60. On the other hand, a groove 67 is provided in the vibrating arm 71 with a neutral line 82 interposed therebetween, and an electrode 69 is disposed in the groove 67. Electrodes 72 and 73 are arranged on the side surface of the vibrating arm 71. The electrode 69 extends to the frame 77.

Although not shown in FIG. 3, grooves and electrodes are also formed on the lower surface of the vibrating arm. That is, the configuration of the groove of the vibrating arm and the arrangement of the electrodes constitute a so-called two-electrode terminal that is configured and connected in the same manner as shown in FIG. 2 of the first embodiment. Also, the relationship between each dimension W, W ₁ , W ₂ , W ₃ , W _{4 and} the relationship between W ₅ , W ₆ , _{WH and} the relationship L, L ₁ , L ₂ , L ₃ , L ₄ , L ₀ , L _t Is the same as in the first embodiment. In this embodiment, one end of the width W ₆ of the frame 77 is formed wider than W ₆ .

Bent crystal resonator of Example 3

  FIG. 4 shows a plan view of a bent crystal resonator 90 that vibrates in the bending mode according to the third embodiment of the present invention. The relationship between the shape and dimensions of the vibrator of this embodiment is the same as that of the first embodiment. In addition, the shape of the vibrator of the present embodiment is a tuning fork shape, and the bent crystal vibrator 90 is configured to include at least a vibrating arm 91, a vibrating arm 92, and a base 93, and one end of the vibrating arm 91 and the vibrating arm 92 is Connected to the base 93. Further, frames 94 and 95 are connected to the base portion 93 via connection portions 96 and 97, respectively. Specifically, one support frame includes a frame 94 and a connection portion 96, and the other support frame includes a frame 95 and a connection portion 97. That is, the support frame is provided so as to protrude from the base portion 93. In addition, the vibrating arm 91 and the vibrating arm 92 each have an upper surface, a lower surface, and a side surface. Further, a groove 100 is provided on the upper surface of the vibrating arm 91 with the neutral line 98 interposed therebetween, that is, so as to include the neutral line 98, and a groove 101 is provided on the upper surface of the vibrating arm 92 in the same manner as the vibrating arm 91. It has been. Further, grooves on the lower surfaces of the vibrating arms 91 and 92 are provided in the same manner as the upper surface (see FIG. 5). Specifically, the groove 100 is provided so as to sandwich the neutral line 98 of the vibrating arm 91. The other vibrating arm 92 is also provided with a groove 101 so as to sandwich the neutral line 99. The vibrator according to this embodiment is fixed to a fixing portion of a container in which the frames 94 and 95 are accommodated with a conductive adhesive or solder. Further, as shown in FIG. 5, electrodes are arranged on the side surfaces of the vibrating arms 91 and 92 and the grooves 100 and 101.

  FIGS. 5A and 5B are cross-sectional views taken along the line BB ′ of the vibrating arms 91 and 92 of the bent crystal resonator 90 of FIG. 5A and 5B, the cross-sectional shape of the vibrating arms 91 and 92 of the bent crystal resonator 90 of FIG. 4 and an example of electrode arrangement will be described in detail. First, in (a), the vibrating arm 91 is provided with grooves 100 and 102. Similarly, the vibrating arm 92 is provided with grooves 101 and 103. Furthermore, electrodes 104 and 105 having the same polarity are disposed in the groove 100 and the groove 102, and electrodes 106 and 107 having the same polarity are disposed in the groove 101 and the groove 103. Further, electrodes 108, 109, 110, and 111 having the same polarity are disposed on the side surfaces of the vibrating arms 91 and 92, and these electrodes are grounded. That is, the ground electrode is represented by the symbol D ″. More specifically, the electrode of the groove of the vibrating arm 91 and the electrode of the groove of the vibrating arm 92 are arranged with different polarities. In the embodiment, a three-electrode terminal DD′-D ″ is configured. That is, one electrode terminal (symbol D) is configured and connected from the electrodes 104 and 105. The other one electrode terminal (symbol D ′) is configured and connected from electrodes 106 and 107. Further, the remaining one electrode terminal (symbol D ″) is a ground electrode (zero polarity), and is configured and connected from electrodes 108, 109, 110, and 111. That is, to the three electrode terminals D, D ′, and D ″. The electrodes to be connected have different polarities. Further, the electrodes will be described in detail. The counter electrodes arranged to oppose the electrodes 108, 109, 110, 111 arranged on both side surfaces of the first vibrating arm 91 and both side surfaces of the second vibrating arm 92 are the first electrode. A part of each of the electrodes on both side surfaces of the first vibrating arm and the second vibrating arm is arranged to face each other.

That is, the groove electrode that opposes the z-axis (thickness) direction of the vibrating arm is configured and arranged so as to have the same polarity and the electrode that opposes the x-axis direction generally has a different polarity. Specifically, the electric field generated perpendicularly to the groove electrode does not exist in the thickness method between the groove electrode opposed to the electrode disposed in the groove provided in the thickness direction. An electrode is disposed on the surface. Now, when a DC voltage is applied between the two electrode terminals D-D '(a positive terminal is applied to the D terminal and a negative electrode is applied to the D' terminal), the electric field Ex works as indicated by an arrow shown in FIG. The electric field Ex is drawn perpendicularly to the electrode by the electrodes arranged opposite to the side surface of the vibrating arm and the side surface in the groove, that is, linearly drawn, so that the electric field Ex is increased, resulting in vibration (tuning fork). At the same time, distortion occurs in the length direction of the arm, and the direction of distortion occurs oppositely on the inside and outside of the vibrating (tuning fork) arm with respect to the neutral line, and the first vibrating (tuning fork) arm and the second vibration The direction of the distortion generated inside the tuning fork is the same as that of the (tuning fork) arm neutral line, and is generated outside the tuning fork with respect to the neutral line of the first vibrating (tuning fork) arm and the second vibrating (tuning fork) arm. The direction of strain to be generated is the same, and the inner strain and the outer strain are generated in opposite directions. Therefore, by applying an alternating voltage between the two electrode terminals D-D ', the vibration (tuning fork) arm vibrates in the fundamental wave mode and in the bending mode of the opposite phase, improving the resonance characteristics and generating. The amount of distortion that occurs is also increased. Therefore, even when the tuning fork-shaped bent quartz crystal is reduced in size, a tuning fork-shaped bent quartz crystal that vibrates in a bending mode having a small equivalent series resistance R ₁ and a high quality factor Q value can be obtained.

The vibration (tuning fork) arm bent crystal resonator 90 has a thickness t, groove has a thickness t _1. The thickness t ₁ here refers to the thickness of the deepest part of the groove. In this embodiment, the cross-sectional shape of the groove is a rectangular shape, but in actuality, the groove has a substantially U shape, or a substantially V shape, or a shape in which a substantially U shape and a substantially V shape are combined. ing. More specifically, the width of the groove gradually decreases as the groove becomes deeper. This is also true for the bent quartz crystal resonators of other embodiments.

  Next, in FIG. 5B, grooves 100 and 102 are provided in the vibrating arm 91. Similarly, the vibrating arm 92 is provided with grooves 101 and 103. Furthermore, electrodes 114, 115, 116, and 117 having the same polarity are disposed in the grooves 100, 101, 102, and 103, and these electrodes are grounded to the ground. That is, the ground electrode. In addition, electrodes 118 and 119 having the same polarity are disposed on the side surface of the vibrating arm 91, and electrodes 120 and 121 having the same polarity are disposed on the side surface of the vibrating arm 92. More specifically, electrodes having different polarities are arranged on the side electrodes of the vibrating arm 91 and the side electrodes of the vibrating arm 92. Therefore, in this embodiment, a three-electrode terminal EE′-E ″ is constituted. That is, one electrode terminal (symbol E) is constituted and connected by electrodes 118 and 119. Other one-electrode terminals (Symbol E ′) is configured and connected from electrodes 120 and 121. Further, the remaining one electrode terminal (symbol E ″) is a ground electrode (zero polarity), and is configured from electrodes 114, 115, 116, and 117. It is connected. That is, the electrodes connected to the three-electrode terminals E, E ′, and E ″ have different polarities. Further, if the electrode is described in detail, the both sides of the first vibrating arm 91 and the both sides of the second vibrating arm 92 The counter electrodes arranged to oppose the arranged electrodes 118, 119, 120, 121 are partially opposed to the electrodes on both sides of the first vibrating arm and the second vibrating arm. .

That is, the groove electrode that opposes the z-axis (thickness) direction of the vibrating arm is configured and arranged so as to have the same polarity and the electrode that opposes the x-axis direction generally has a different polarity. Specifically, the electric field generated perpendicularly to the groove electrode does not exist in the thickness method between the groove electrode opposed to the electrode disposed in the groove provided in the thickness direction. An electrode is disposed on the surface. Now, when a DC voltage is applied between the two electrode terminals EE ′ (a positive electrode is applied to the E terminal and a negative electrode is applied to the E ′ terminal), the electric field Ex works as indicated by an arrow shown in FIG. The electric field Ex is drawn perpendicularly to the electrode by the electrodes arranged opposite to the side surface of the vibrating arm and the side surface in the groove, that is, linearly drawn, so that the electric field Ex is increased, and as a result, the tuning fork shape is bent. even when a crystal oscillator was miniaturized, small equivalent series resistance R _1, the flexural quartz oscillator tuning fork vibrating at a high bending mode quality factor Q value is obtained. Further, if the vibration arm and the electrodes disposed thereon are described in detail, the vibration arm is composed of a plurality (pieces) of the groove arm provided on the upper and lower surfaces or the upper and lower surfaces of the vibration arm and the side surface of the vibration arm. The ground electrode is disposed on at least one surface, the electrode serving as the positive electrode is disposed on at least one surface, and the electrode serving as the negative electrode is disposed on at least one surface. In other words, the electrodes are formed so as to be three-electrode terminals, and the electrodes are arranged so that the vibrating arm vibrates in the fundamental wave mode of the bending mode and in the opposite phase.

Bent crystal resonator of Example 4

FIG. 6 is a plan view of a tuning fork-shaped bent quartz crystal resonator 130 that vibrates in the bending mode according to the fourth embodiment of the present invention. The vibrator 130 has tuning fork arms 131 and 132 and grooves 133 and 134. That is, the bent quartz crystal resonator 130 of the present embodiment has a shape when L ₂ = L _{3 in} the first embodiment. Although not shown in the figure, grooves and electrodes are also provided on the back surface, and are configured as in the first embodiment.

Bent quartz resonator of Example 5

FIG. 7 shows a plan view of a tuning-fork-shaped bent quartz crystal resonator 140 that vibrates in the bending mode according to the fifth embodiment of the present invention. The vibrator 140 has tuning fork arms 141 and 142 and grooves 143 and 144. That is, the bent quartz crystal resonator 140 of the present embodiment has a shape when L ₂ = L _{3 in} the _second embodiment.

Bent crystal resonator of Example 6

FIG. 8 is a plan view of a tuning-fork-shaped bent crystal resonator 145 that vibrates in the bending mode according to the sixth embodiment of the present invention. The vibrator 145 has tuning fork arms 146 and 147 and grooves 148 and 149. In other words, the bent crystal resonator 145 of this embodiment has a shape in which the notches 150 and 151 are formed in the connection portion or frame of the resonator of the fourth embodiment. At the same time, the tuning fork arm (vibration portion) has a shape in which the arm width of the tip portion is widened. With this structure, the tuning fork arm has a mass effect. Therefore, the arm length can be shortened even at the same frequency, and the size can be reduced. Actually, the length of the tuning fork arm that widens the arm width is widely formed from the tip portion, which is the free end of the tuning fork arm, to a position about half the length of the arm. That is, a wide width is provided at an arbitrary position within the range. Further, in this embodiment, the groove is provided in the tuning fork arm, but the groove may be provided to extend to the base. In addition, the bent crystal resonators of the first to sixth embodiments are excited by the piezoelectric constant e ₁₂ (= e ′ ₁₂ ), and the larger the absolute value, the better the electromechanical conversion efficiency. The absolute value of piezoelectric constant _{e 12} of the flexural crystal oscillator of the present invention have a 0.095C / ^{m 2} greater than. In particular, the fundamental mode vibration, in order to obtain a smaller equivalent series resistance _{R 1, preferably,} the absolute value of _{e 12} is in the range of ^{0.12C / m 2 ~0.19C / m 2} . However, the piezoelectric constant e ₁₁ = 0.171 C / m ² and the piezoelectric constant e ₁₄ = −0.0406 C / m ² of quartz were used for the calculation of e ₁₂ .

Crystal unit of Example 1

  FIG. 9 is a top view of the crystal unit 120 according to the first embodiment of the present invention. The surface mount type case 165 is provided with fixing portions 166 and 167. Further, the crystal unit 120 of this embodiment includes a tuning fork-shaped bent crystal resonator 10, a case 165, and a lid (not shown). More specifically, the frames 36 and 37 of the vibrator 10 are fixed to fixing portions 166 and 167 provided on the case 165 with conductive adhesives 168 and 169 or solder. In addition, the case 165 and the lid are joined via a joining member. In the present embodiment, the vibrator is fixed to the case at two locations of the frame, but it may be additionally fixed at the tuning fork base or the connecting portion. Moreover, you may provide a fixing | fixed part in a lid | cover. Further, the bent crystal resonator 90 of the third embodiment may be mounted instead of the resonator 10. In this case, for example, a three-electrode terminal is configured on the frame, and the fixed portion is also configured with three electrodes connected to these electrodes.

Crystal unit of Example 2

  FIG. 10 is a top view of the crystal unit 170 according to the second embodiment of the present invention. The surface mount type case 175 is provided with fixing portions 176 and 177. In addition, the crystal unit 170 of this embodiment includes a tuning fork-shaped bent crystal resonator 50, a case 175, and a lid (not shown). More specifically, the frame 77 of the vibrator 50 is fixed to fixing portions 176 and 177 provided on the case 175 with conductive adhesives 178 and 179 or solder. In addition, the case 175 and the lid are joined via a joining member. Further, in the case of using a three-electrode terminal bent quartz crystal resonator, three divided electrodes are formed in which a fixing portion for fixing the resonator is also connected to these electrodes. These electrodes are arranged so as to extend to the outside (rear surface) of the container (for example, the case).

  In addition, the tuning-fork-shaped bent quartz resonators of the third to sixth embodiments are also fixed at least on the frame using a conductive adhesive or the like, similar to the configuration of the quartz crystal unit. The crystal unit of the embodiment is connected to a circuit element (CMOS inverter, resistor, capacitor) and is electrically connected to a two-electrode terminal or a three-electrode terminal provided outside the crystal unit. That is, only a tuning fork-shaped bent quartz crystal is housed in the unit. At this time, the bent crystal resonator is housed in a vacuum unit. Further, the case member is made of ceramic or glass, the lid member is made of metal or glass, and the joining member is made of metal or low-melting glass. Further, unlike the above configuration, the tuning fork-shaped bent quartz crystal resonators of the first to sixth embodiments may be housed in a container (unit) together with the circuit elements.

Example 1 Crystal Oscillator

  FIG. 11 is an example of a crystal oscillation circuit diagram constituting the crystal oscillator of Example 1 of the present invention. In this embodiment, the crystal oscillation circuit 1 includes an amplifier (CMOS inverter) 2, a feedback resistor 4, a drain resistor 7, capacitors 5 and 6, and a tuning fork-shaped bent crystal resonator 3. That is, the crystal oscillation circuit 1 includes an amplifier circuit 8 including an amplifier 2 and a feedback resistor 4, a drain resistor 7, capacitors 5 and 6, and a feedback circuit 9 including a bent crystal resonator 3. In detail, the crystal oscillation circuit of the present invention is composed of an amplifier circuit and a feedback circuit, the amplifier circuit is composed of at least an amplifier, and the feedback circuit is composed of at least a tuning-fork-shaped bent crystal resonator and a capacitor. . The tuning fork-shaped bent quartz crystal used in the crystal oscillator of the present invention is the bent quartz crystal described in the first to sixth embodiments, and the vibrator is accommodated in a container (unit). A so-called crystal unit is used.

FIG. 12 shows the feedback circuit diagram of FIG. Now, the angular frequency of the tuning-fork-shaped crystal resonator that vibrates in the bending mode is ω _i , the resistance of the drain resistor 7 is R _d , the capacitances of the capacitors 5 and 6 are C _g and C _d , and the crystal impedance of the crystal is R _ei , When the input voltage is V ₁ and the output voltage is V ₂ , the feedback rate β _i is defined by β _i = | V ₂ | _i / | V ₁ | _i . However, i represents the vibration order of the bending vibration mode. For example, when i = 1, it is fundamental wave mode vibration, and when i = 2, it is second harmonic mode vibration. Further, the load capacity C _L is given by C _L = C _g C _d / (C _g + C _d ). When C _g = C _d = C _gd and R _d >> R _ei , the feedback rate β _i is β _i = 1 / (1 + kC _L ² ). However, k is expressed by a function of ω _i , R _d , and R _ei . R _ei is approximately equal to the equivalent series resistance R _i .

Thus, from the relationship between the feedback rate β _i and the load capacitance C _L , it is well understood that the feedback rates of the fundamental mode vibration and the harmonic mode vibration increase as C _L decreases. Thus, the C _L decreases, towards the second harmonic mode vibration tends to oscillate than the fundamental mode vibration. The reason is that since the maximum vibration amplitude of the harmonic mode vibration is smaller than the maximum vibration amplitude of the fundamental mode vibration, the amplitude condition and the phase condition which are oscillation continuation conditions are satisfied simultaneously.

The crystal oscillator using the bent crystal resonator according to the present invention provides a crystal oscillator having a fundamental mode oscillation frequency with low current consumption and high frequency stability (high time accuracy). The purpose is that. Therefore, in order to reduce current consumption, the load capacitance _{C L} is used below 18 pF. In order to further reduce the current consumption, since the current consumption is proportional to the load capacity, C _L = 14 pF or less is preferable. Further, in order to suppress the vibration of the second harmonic mode and the output signal of the oscillator obtains the oscillation frequency of the fundamental mode vibration, α ₁ / α ₂ > β ₂ / β ₁ and α ₁ β ₁ > 1 are satisfied. Thus, the oscillation circuit of this embodiment is configured. Where α ₁ and α ₂ are the amplification factors of the fundamental wave mode vibration and the second harmonic mode vibration amplification circuit, and β ₁ and β ₂ are the feedback factors of the feedback circuit of the fundamental wave mode vibration and the second harmonic mode vibration. It is.

In other words, the ratio between the amplification factor α ₁ of the fundamental mode vibration of the amplifier circuit and the amplification factor α ₂ of the second harmonic mode vibration is equal to the feedback factor β ₂ of the second harmonic mode oscillation of the feedback circuit and the fundamental wave. greater than the ratio of the feedback factor beta ₁ mode vibration, and the product of the feedback factor beta ₁ amplification factor alpha ₁ and the fundamental mode vibration of the fundamental wave mode vibration is configured to be greater than 1. With such a configuration, it is possible to realize a crystal oscillator that consumes less current and whose output signal has an oscillation frequency of fundamental mode vibration. The output signal of the crystal oscillation circuit is output via a buffer circuit. Furthermore, in order to obtain an optimum feedback factor of the fundamental mode oscillation, but the drain resistance _{R d} is usually 200kΩ within the 1 M.OMEGA, preferably, 600Keiomega is used from 300Keiomega.

Further, the amplifying part of the amplifying circuit constituting the crystal oscillation circuit of the present embodiment can exhibit the characteristic by a negative resistance -RL _i . When i = 1, it is a negative resistance of fundamental mode vibration, and when i = 2, it is a negative resistance of second harmonic mode vibration. In the crystal oscillator of the present embodiment, the ratio of the absolute value | −RL ₁ | of the negative resistance of the fundamental mode vibration of the amplifier circuit to the equivalent series resistance R ₁ of the fundamental mode vibration is the second harmonic mode of the amplifier circuit. The oscillation circuit is configured to be larger than the ratio between the absolute value | −RL ₂ | of the negative resistance of vibration and the equivalent series resistance R ₂ of the _second harmonic mode vibration. That is, it is configured to satisfy | −RL ₁ | / R ₁ > | −RL ₂ | / R ₂ . Preferably, it has a relationship of | -RL ₁ | / R ₁ >1> | -RL ₂ | / R ₂ . With such a configuration of the crystal oscillation circuit, the oscillation activation of the second harmonic mode vibration can be suppressed, so that the oscillation frequency of the fundamental mode vibration can be obtained as an output signal. In particular, in order to achieve the above-described object with an ultra-miniaturized tuning-fork-shaped bent quartz crystal, as an example, when the reference frequency of the fundamental mode vibration is 32.768 kHz (oscillation frequency is approximately 32.768 kHz), the basic The absolute value | -RL ₁ | of the negative resistance in the amplification section in the wave mode vibration is larger than 80 kΩ, and the absolute value | -RL ₂ | of the negative resistance in the amplification section of the second harmonic mode vibration is It is necessary to be smaller than 75 kΩ. In addition, the electrode configuration of the bent crystal unit constituting the crystal oscillation circuit of the present embodiment is a two-electrode terminal, but a bent crystal unit having a three-electrode terminal may be used. In this case, (a ) And the ground electrode shown in (b) may be added to the crystal unit 3. In the case of a three-electrode terminal, the capacitance between electrodes that generate an electric field is the same as the parallel capacitance C ₀ between the two-electrode terminals. That is, the result of C ₀ is the same for both the two-electrode terminal and the three-electrode terminal.

Although the present invention has been described based on the illustrated example, the present invention is not limited to the above-described example, and in the tuning-fork-shaped bent quartz resonators of the first to sixth embodiments, the groove sandwiches the neutral line (including the neutral line). However, the present invention is not limited to this, and grooves may be formed on both sides of the neutral fork. In this case, partial width W ₇ including the neutral line of the tuning fork arms are formed to be smaller than 0.05 mm. The width of each groove is formed to be smaller than 0.04 mm, and the ratio between the groove thickness t ₁ and the tuning fork arm thickness t is 0.79 or less. By thus forming, it can be larger than M ₂ and M _1. Further, in this embodiment, the partial width W ₇ may be provided continuously in the length direction of the tuning fork arm or may be provided discontinuously. That is, it is provided partially. Specifically, it is provided so that there is a step in the length direction. By forming such a partial width W ₇ , the outer shape of the tuning fork and the groove can be formed at the same time, and the number of steps can be reduced, so that an inexpensive crystal resonator can be realized.

  Further, as an example, a tuning fork arm that is a vibrating arm is composed of a first tuning fork arm and a second tuning fork arm, and grooves are provided on the upper and lower surfaces of the first tuning fork arm and the second tuning fork arm in the thickness direction, respectively. The groove is provided with two grooves on the upper and lower surfaces in the width direction, leaving all or part of the neutral line of the first tuning fork arm and the second tuning fork arm. Further, in each groove, electrodes having different polarities between the electrode of the groove of the first tuning fork arm and the electrode of the groove of the second tuning fork arm are arranged, and the tuning fork arm arranged opposite to the electrode of the groove is arranged. Two electrode terminals having different polarities from those of the side electrodes are formed. Among the two electrode terminals, one electrode terminal is disposed on both sides of the first tuning fork arm and the second tuning fork arm. The electrodes arranged in the upper and lower grooves and the electrodes arranged on both sides are connected, and the other one electrode terminal is arranged on both sides of the first tuning fork arm. The electrodes are arranged in the grooves on the upper and lower surfaces of the second tuning fork arm, and the electrodes arranged on both side surfaces are connected to the electrodes arranged in the grooves on the upper and lower surfaces.

Further, the capacity ratio r ₁ in the fundamental mode vibration of the tuning fork-shaped bent quartz crystal of the first to sixth embodiments is configured to be smaller than the capacity ratio r ₂ of the second harmonic mode vibration. . With such a configuration, with respect to the same change in the load capacitance C _L, greater than the frequency change of the bending quartz oscillator frequency change of the bending quartz oscillator which oscillates at the fundamental mode oscillates at the second harmonic mode. That is, the fundamental mode vibration can take a wider frequency variable range than the second harmonic mode vibration. More specifically, in the vicinity of C _L = 18 pF, if the C _L value changes by 1 pF, the frequency change of the fundamental mode vibration becomes larger than the frequency change of the second harmonic mode vibration. Therefore, the fundamental mode vibration has significant effect even with a small variable amounts of C _L, can widen the variable range of frequency. Thereby, since the range of the variable capacitance of the capacitor can be reduced, the number of capacitors to be used can be reduced. As a result, an inexpensive crystal oscillator can be obtained. Further, the capacitance ratio r ₁ in the fundamental mode vibration of the tuning fork-shaped bent quartz crystal of each of the above embodiments is in the range of 250 to 480, and the capacitance ratio r ₂ has a value greater than 1200.

The capacitance ratios r ₁ and r ₂ of the tuning fork-shaped bent quartz crystal resonator are given by r ₁ = C ₀ / C ₁ and r ₂ = C ₀ / C ₂ , respectively. However, C ₀ is a shunt capacitance electrical equivalent circuit, C ₁ and C ₂ is the equivalent capacitance of the fundamental mode vibration and second harmonic mode vibration of an equivalent circuit. That is, C ₀ is the total capacitance between the terminals, between the two electrode terminals or between the three electrode terminals of the bent crystal resonator. In other words, it is the capacitance between electrodes where an electric field is generated. Further, the quality factor of the fundamental mode vibration and the second harmonic mode vibration of the tuning fork-shaped bent quartz crystal resonator is given by Q ₁ value and Q ₂ value. In each of the tuning fork-shaped bent quartz resonators of the above-described embodiments, the dependency of the resonance frequency oscillating in the fundamental wave mode due to the parallel capacitance is smaller than the dependency of the resonance frequency oscillating in the second harmonic mode due to the parallel capacitance. Configured as follows. That is, it is configured to satisfy r ₁ / 2Q ₁ ² <r ₂ / 2Q ₂ ² . With this configuration, the influence of the parallel capacitance of the resonance frequency oscillating in the fundamental wave mode is so small that it can be ignored, so that a tuning-fork-shaped bent quartz crystal oscillating in the fundamental wave mode having high frequency stability is obtained. Further, in the present invention, r ₁ / 2Q ₁ ² and r ₂ / 2Q ₂ ² are respectively set as S ₁ and S ₂ , and S ₁ and S ₂ are respectively frequency-stable for fundamental mode vibration and second harmonic mode vibration. Called coefficient. That is, S ₁ = r ₁ / 2Q ₁ ² and S ₂ = r ₂ / 2Q ₂ ² are given. Further, it is usually preferable to provide the groove and the electrode so as to have a relationship of Q ₁ > Q ₂ , but when R ₂ is in the range of R ₂ ▲ to ▼ (1-3) R ₁ , Q ₁ <there is a case in which the relationship of Q ₂ is obtained.

In addition, the electromechanical coupling coefficient of the fundamental mode vibration of the vibrator described in each of the above embodiments is larger than the electromechanical coupling coefficient of the second harmonic mode vibration, and the equivalent series resistance R ₁ of the fundamental mode vibration. Is in the range of 35 kΩ to 105 kΩ. R ₂ has a relationship of R ₂ / R ₁ > 1. That is, the groove and the electrode are configured to satisfy the relationship of R ₂ > 35 kΩ. Furthermore, the crystal oscillator of the present invention aims to provide a crystal oscillator in which the oscillation frequency of the fundamental wave mode vibration is obtained as an output signal and the oscillation rise time _tr is within 1 second. Therefore, it is necessary to satisfy the relationship of | -RL ₁ | -R ₁ ▲ ≧ ▼ 2L _m1 . However, in the present invention, _tr refers to the time to reach 80% of the maximum output voltage of the crystal oscillation circuit. L _m1 is an equivalent inductance of an electrical equivalent circuit in a fundamental mode vibration of a tuning fork-shaped bent quartz crystal resonator. Furthermore, in order to shorten the _{t r,} for example, in order to _{t r} ▲ ≦ ▼ 0.4 seconds, | _-RL 1 | is required to satisfy a relation of -R ₁ ▲ ≧ ▼ _{5L m1.} The absolute value of the negative resistance | -RL ₁ | a not so large, the equivalent inductance of the fundamental mode vibration of the vibrator of the present invention in order to shorten the _{t r} (reference frequency 32.768kHz) _{L m1} Is less than 12 kH, preferably 109 kH or less. Although the reference frequency of 32.768 kHz is used as the reference frequency in the fundamental mode vibration of the tuning-fork-shaped bent quartz crystal of each of the above embodiments, the present invention is not limited to this frequency, and the reference frequency of 10 kHz to 200 kHz is used. Applied.

Further, as an example, in order to obtain an oscillation frequency as an output frequency where the reference frequency of the tuning-fork-shaped bent quartz crystal resonator is 32.768 kHz and the output signal of the crystal oscillation circuit is within 32.768 kHz ± 100 ppm (parts per million), First, a vibrator is formed in a quartz wafer by a photolithography method and an etching method so that the frequency is higher than 32.768 kHz. Next, after fixing to the fixing part of the container for housing the vibrator, a weight is added to the tuning fork arm so that an oscillation frequency within 32.768 kHz ± 100 ppm is obtained as an output frequency of the output signal of the crystal oscillation circuit. After adjusting the frequency or attaching a weight to the tuning fork arm so that the frequency is lower than 32.768 kHz, and fixing the tuning fork arm to the fixing portion of the container for housing the vibrator, the output signal of the crystal oscillation circuit is 32.768 kHz. The frequency is adjusted by removing the weight of the tuning fork arm so that an oscillation frequency within ± 100 ppm is obtained as the output frequency. In this embodiment, the load capacitance C _L value of the crystal oscillator circuit is used below 18 pF. Furthermore, for the frequency adjustment, at least one of a so-called ion etching method or sputtering method using a laser beam, vapor deposition, electron beam, and ionized atoms and molecules is used. Further, in this embodiment, after the vibrator is formed in the quartz wafer so that the frequency is higher than 32.768 kHz, a step of inspecting whether the vibrator is a good vibrator or a defective vibrator in the quartz wafer may be added. . That is, when a defective vibrator is present, the defective vibrator is removed from the quartz wafer, or some marking is made on the vibrator, or the vibrator is stored in the computer.

  Further, the tuning fork shape and the groove of the bent quartz crystal resonator of this embodiment are processed using at least one of chemical, physical and mechanical methods. In the physical method, for example, so-called particles such as ionized atoms and molecules are scattered and processed. In the mechanical method, for example, particles for blasting are scattered and processed. In the above example, since particles are used for processing, in the present invention, this is called (etching) processing by a particle method.

  Since the crystal resonator, crystal unit, and crystal oscillator of the present invention are ultra-compact and have high frequency stability, they are particularly applicable to portable devices and consumer devices that are ultra-compact and require high frequency stability.

The top view of the bending crystal oscillator which vibrates in the bending mode of Example 1 of this invention is shown. FIG. 2 is a cross-sectional view taken along the line AA ′ of the vibrating arm of the bent crystal resonator of FIG. The top view of the bending crystal oscillator which vibrates in the bending mode of Example 2 of this invention is shown. The top view of the bending crystal oscillator which vibrates in the bending mode of Example 3 of this invention is shown. (A) And (b) shows BB 'sectional drawing of the vibrating arm of the bending crystal oscillator of FIG. FIG. 6 is a plan view of a tuning fork-shaped bent quartz crystal resonator that vibrates in a bending mode according to a fourth embodiment of the present invention. FIG. 10 is a plan view of a tuning fork-shaped bent quartz crystal resonator that vibrates in a bending mode according to a fifth embodiment of the present invention. The top view of the bending crystal oscillator of the tuning fork shape which vibrates in the bending mode of Example 6 of this invention is shown. It is a top view of the crystal unit of Example 1 of this invention. It is a top view of the crystal unit of Example 2 of the present invention. 1 shows one embodiment of a crystal oscillation circuit diagram constituting the crystal oscillator of Embodiment 1 of the present invention. The feedback circuit diagram of FIG. 11 is shown.

Explanation of symbols

W _H , W _S tuning fork base width, connection width W ₄ , W ₅ , W ₆ tuning fork arm spacing, tuning fork arm full width, frame width L ₀ , L ₁ groove length, tuning fork base length L ₂ , L ₃ connecting part length, frame length L _t Overall length of tuning fork

Claims (6)

In a portable device equipped with a crystal oscillator configured to include an amplifier circuit configured to include at least an amplifier and a crystal oscillation circuit including a feedback circuit configured to include at least a crystal resonator and a capacitor,
The quartz oscillator is a tuning fork-shaped bent quartz oscillator including a base, a first vibrating arm connected to the base, and a second vibrating arm, and includes a first vibrating arm and a second vibrating arm. Each has an upper surface, a lower surface, and a side surface, and the base is connected to one frame through one connection portion and is connected to the other frame through the other connection portion. The frame and the other frame are formed on the outer side of the tuning fork different from the tuning fork fork, and extend in the same direction as the first vibrating arm and the second vibrating arm, and the one frame and the other frame are Grooves are formed in each of the upper surface and the lower surface of each of the first vibrating arm and the second vibrating arm at positions opposite to each other with respect to the base, and the first vibrating arm and the first vibrating arm Each of the two vibrating arms includes a distal end that is a free end and the distal end. And having one end connected to the base, and having two different widths between the tip and the one end, and one of the two different widths is The other one of the two different widths is located on the one end side opposite the tip side, and the tip part The groove formed in each of the upper surface and the lower surface of each of the first vibrating arm and the second vibrating arm is smaller than the width located on the side of the first vibrating arm and the second vibrating arm. Formed on each of an upper surface and a lower surface of a vibrating arm having a width located on each of the one end portions, and the one frame and the other frame are fixed to a fixing portion of a case, The case is equipped with a crystal oscillator characterized by being bonded to the lid via a bonding member. Equipment. According to claim 1, wherein the bent crystal oscillator provided with a full Iga of merit M ₂ of full Iga of merit M ₁ of the fundamental wave mode vibration second harmonic mode vibration, Fuigaobu of the fundamental mode vibration portable device benefits M ₁ is equipped with a crystal oscillator, wherein greater than the second harmonic mode vibration off Iga of merit M _2. 3. The amplifier according to claim 1, wherein the amplifier includes an absolute value | −RL ₁ | of a negative resistance in the fundamental wave mode vibration of the bent quartz crystal, and the fundamental wave mode vibration of the bent quartz crystal is equivalent to comprise a series resistor _{R 1} and the equivalent inductance _{L m1,} the absolute value of the negative resistance | -RL ₁ | between said equivalent series resistance _{R 1} and the equivalent inductance _{L m1} is, | -RL ₁ A portable device equipped with a crystal oscillator characterized by having a relationship of | -R ₁ ▲ ≧ ▼ 2L _m1 . In a method of manufacturing a portable device equipped with a crystal oscillator including an amplification circuit including at least an amplifier and a crystal oscillation circuit including a feedback circuit including at least a crystal resonator and a capacitor,
The quartz oscillator is a tuning fork-shaped bent quartz oscillator including a base, a first vibrating arm connected to the base, and a second vibrating arm, and includes a first vibrating arm and a second vibrating arm. Each has an upper surface, a lower surface, and a side surface, and the base is connected to one frame through one connection portion and is connected to the other frame through the other connection portion. The frame and the other frame are formed on the outer side of the tuning fork different from the tuning fork fork, and extend in the same direction as the first vibrating arm and the second vibrating arm, and the one frame and the other frame are Grooves are formed in each of the upper surface and the lower surface of each of the first vibrating arm and the second vibrating arm at positions opposite to each other with respect to the base, and the first vibrating arm and the first vibrating arm Each of the two vibrating arms includes a distal end that is a free end and the distal end. And having one end connected to the base, and having two different widths between the tip and the one end, and one of the two different widths is The other one of the two different widths is located on the one end side opposite the tip side, and the tip part The groove formed in each of the upper surface and the lower surface of each of the first vibrating arm and the second vibrating arm is smaller than the width located on the side of the first vibrating arm and the second vibrating arm. Formed on each of an upper surface and a lower surface of a vibrating arm having a width located on each of the one end portions, and the one frame and the other frame are fixed to a fixing portion of a case, The case is bonded to the lid via a bonding member, and the frequency of the bent crystal resonator is adjusted. Manufacturing method for a portable device that was equipped with a crystal oscillator, characterized in that comprises a step of. 5. The tuning fork-shaped bent quartz crystal resonator according to claim 4, comprising a tuning fork arm having a first vibrating arm and a second vibrating arm, and the tuning fork shape having the tuning fork arm having a frequency higher than 32.768 kHz. The bent crystal resonator is formed in a crystal wafer, and after the formation, a weight is attached to the tuning fork arm of the bent crystal resonator so that the frequency is lower than 32.768 kHz. The bending crystal resonator having a frequency lower than 32.768 kHz is fixed to the fixing portion, and after the fixing, the output frequency of the output signal of the crystal oscillation circuit configured to include the bending crystal resonator including the tuning fork arm is The crystal oscillation is characterized in that the frequency is adjusted by removing the weight of the tuning fork arm of the bent crystal resonator so that it is within a range of −100 ppm to +100 ppm with respect to 32.768 kHz. Equipped with the manufacturing method for a portable equipment. In claim 4 or claim 5, wherein the bent crystal oscillator and the capacitance ratio r ₁ and the quality factor Q _1, frequency stability factor S ₁ of the fundamental wave mode vibration, volume ratio of the second harmonic mode oscillation r ₂ and quality S ₁ is smaller than S ₂ when it has a coefficient Q ₂ and a frequency stability coefficient S ₂ and is defined by S ₁ = r ₁ / 2Q ₁ ² and S ₂ = r ₂ / 2Q ₂ ² A method for manufacturing a portable device equipped with a crystal oscillator.

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