JP3248630B2 - Direct bonding method of crystal blank and crystal resonator, crystal oscillator and crystal filter using the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quartz crystal unit in which at least two quartz pieces are directly bonded without any intervening material such as an adhesive, and a cellular phone and the like constituted by using the quartz crystal unit. The present invention relates to a crystal device that can be used for mobile communication equipment.

[0002]

2. Description of the Related Art In recent years, with the spread of mobile communication devices such as portable telephones, demands for crystal devices used for reference frequency sources and filters of those devices have been increasing.

An example of a conventional crystal device will be described below with reference to the drawings.

FIG. 32 is a side view of a main part showing each example of the configuration of a conventional crystal unit. In FIG. 32, 401 and 4
03 is a crystal blank, and 402 and 404 are excitation electrodes. Quartz pieces 401 and 403 are processed into a disk or lens shape by mechanical and chemical processing.

[0005] Quartz pieces 401, which are such piezoelectric materials,
When an electric field is applied to the excitation electrodes 402 and 404 opposed to each other via 403, distortion occurs in the crystal blanks 401 and 403, and resonance can be performed at a frequency determined by the elastic constant and the shape dimensions of the crystal. 2. Description of the Related Art Conventionally, a crystal resonator used in a mobile communication device is called an AT-cut crystal resonator (having a cutout angle of around 54.75 °) and is a resonator utilizing thickness shear vibration. Here, the cutout angle is an angle between the normal to the plate surface and the Z axis of the quartz crystal. A BT cut crystal resonator having a cutout angle of about 135.00 ° with respect to the AT cut is called a BT cut crystal resonator. The resonance frequency-temperature characteristic of the AT-cut quartz resonator is determined by the cut-out angle.
As shown in FIG. 3, the resonance frequency-temperature characteristic of the conventional AT-cut crystal blank is a cubic curve, and the frequency deviation amount (vertical axis) in the temperature range of 0 to 50 ° C. (horizontal axis) is ±
A frequency stability of 1.0 ppm is obtained. (For example,
'Piezo Electrocity'; Walter Guyton
Caddy, Dover Publishing ('Piezoselect
righty '; edited by Walter
Guyton CADY, Dover Publ. , I
nc. ) Or "On the adiabatic elastic constant of quartz and its temperature characteristics"; Masanao Ariga, Tokyo Institute of Technology, Bulletin of Showa 3
(Issued December 2013, p. 88). As a method for increasing the frequency stability, substances having different coefficients of linear expansion are grown on a quartz substrate (Japanese Patent Application Laid-Open No. 55-138914) or mounted (Japanese Patent Application Laid-Open Nos. 55-158718 and 56-6189).
No. 9) has been proposed.

Further, as shown in FIG. 32A, the crystal blank 401 is formed into a shape such as an optical lens in which the central portion is thicker than the peripheral portion (convex processing), or FIG.
As shown in FIG. 2 (b), the elastic electrode is confined in the central portion by increasing the thickness of the central portion of the excitation electrode to increase the Q value.
(For example, JP-A-2-260910).

[0007] In addition to the above convex processing, there is bevel processing in which the corners of one or both sides of a crystal blank are dropped.

As a method of extracting a plurality of vibrations from one crystal resonator, a method of partially thinning a crystal blank by a chemical polishing method, a method of using a fundamental mode and a higher mode simultaneously, and the like are considered. .

Next, a conventional crystal oscillator, an analog temperature compensation crystal oscillator, and a digital temperature compensation crystal oscillator will be described with reference to the drawings.

[0010] A crystal oscillator is an oscillator that uses a crystal oscillator having a Q of about 100,000 as a resonance element to stabilize the frequency. Therefore, the output frequency-temperature characteristic of the crystal oscillator depends on the resonance frequency-temperature characteristic of the crystal unit,
When a conventional AT-cut quartz resonator is used, FIG.
As shown in the figure, a frequency stability of ± 1.0 ppm is obtained in a temperature range of 0 to 50 ° C. However, a crystal oscillator used in a mobile phone has a temperature range of -30 ° C to 80 ° C.
A frequency stability of 1.0 ppm is required, and a temperature compensation circuit is required to satisfy the requirement. A crystal oscillator provided with a temperature compensation circuit is called a temperature compensation crystal oscillator, and can be roughly classified into an analog system and a digital system.

FIGS. 34 and 35 show typical circuit configurations of a conventional analog temperature compensation crystal oscillator and a conventional digital temperature compensation crystal oscillator, respectively.

In FIG. 34, reference numeral 411 denotes an oscillation circuit;
2 is an output terminal, 413 is a crystal oscillator, and 414 is a temperature compensation circuit. The temperature compensating circuit 414 is configured using a temperature-sensitive element such as a thermistor, a capacitive element such as a capacitor or a varactor diode, and a resistor. The reactance changes according to the temperature, and the temperature of the reactance (resonance frequency) of the crystal unit 413 is changed. To compensate for the change due to the above, and stabilize the output frequency.

In FIG. 35, reference numeral 421 denotes a temperature sensor,
Reference numeral 22 denotes an A / D converter, 423 denotes a storage device, 424 denotes a variable reactance circuit, 425 denotes an oscillation circuit, and 426 denotes a crystal oscillator. Reference numeral 427 denotes a digitally controlled crystal oscillator including a variable reactance circuit 424, an oscillation circuit 425, and a crystal oscillator 426. The storage device 423 stores in advance data in which a digital signal obtained by converting an output signal of the temperature sensor 421 by the A / D converter 422 corresponds to a control signal of the variable reactance circuit 424.
As a result, the reactance of the variable reactance circuit 424 changes in response to the temperature change, and the oscillation output frequency is stabilized by compensating the resonance frequency-temperature characteristic of the crystal unit 426.

The temperature sensor 421 and the quartz oscillator 42
In order to suppress the temperature difference due to the difference in the installation location and the difference in thermal time constant of 6, a method of extracting a fundamental wave and a higher-order overtone or sub-vibration from one piece of crystal is considered (for example, JP-A-2-170607 and JP-A-2-17
No. 4407).

Next, an example of a conventional crystal filter will be described with reference to the drawings.

FIGS. 36A and 36B show the structure of a conventional quartz filter. FIG. 36A is a perspective view, and FIG.
It is sectional drawing in a '. In FIG. 36, reference numeral 431 denotes a crystal blank and reference numerals 432, 433, and 434 denote electrodes, which are opposed to each other via the crystal blank 431. The electrodes 432,
The crystal at the portion where 433 and 434 face each other is thinner than the peripheral portion.

The operation of the thus configured quartz filter will be described below.

The electrode 434 is normally grounded, and the remaining two electrodes 432 and 433 become electrodes for inputting and outputting electric signals. For example, when an electric signal is input to the electrode 432, the crystal blank 431 resonates at a frequency determined by its thickness and elastic constant. This resonance mechanically transmits through the crystal blank 431, and as a result, an electric field is generated between the electrodes 433 and 434, so that an electric signal can be extracted from the electrode 433. That is, it becomes a band-pass filter having a resonance frequency determined by the thickness and the elastic constant of the crystal blank 431. In this configuration, the central portion is thinned by a chemical polishing method in order to increase the resonance frequency.
[For example, Proceedings of the 39th Annual Frequency Control Symposium, pp. 481-485, Fabrication of VHF band monolithic quartz filter by ion milling method (Proc. 39th Ann. Frequency.)
y Control Symposium, pp. 4
81-485 'VHF MONOLITHIC CRY
STAL FILTERS FABRICATED B
Y CHEMICAL MILLING ')]

[0019]

However, it is difficult to three-dimensionally process the crystal blank only by mechanical and chemical polishing as described above, and the processing time is long. Had a point.

Further, there is a limit in improving the stability of the crystal resonator only by the cutout angle. Further, in the method of growing or mounting different substances on the crystal substrate, these substances reduce the elastic vibration of the crystal. It has a problem that it becomes a hindering resistor and deteriorates the Q of the crystal resonator.

As a method of increasing Q, the method of convex processing of a quartz piece has a problem that the accuracy of the resonance frequency is reduced. On the other hand, the method of depositing electrode films having different sizes many times is time-consuming. Had problems such as

Further, in the method of extracting two vibrations using the fundamental mode and the higher-order mode of a single crystal piece, the resonance frequency and the temperature characteristics cannot be set separately.

Further, since the resonance frequency of the crystal unit has a temperature characteristic, a temperature compensator such as a temperature compensation circuit or a thermostat is required for the reference oscillator using the crystal unit. The former is a method in which the oscillation frequency is changed by using a thermistor or the like to change the impedance of the temperature compensation circuit so as to cancel the resonance frequency-temperature characteristics of the crystal resonator. This is a method of keeping these at a constant temperature to keep the oscillation frequency constant.

First, according to the former method, a special temperature characteristic control circuit is required, the number of circuit components is large, and adjustment work is also required, resulting in a problem that the cost is increased. On the other hand, in the latter method, the volume occupied by the thermostat is large, and the current consumption is further increased.

Further, since the resonance frequency of the crystal unit is determined by the thickness of the crystal blank, one crystal unit has one resonance frequency.
If only one resonance frequency can be obtained and multiple resonance frequencies are required, it is necessary to prepare a crystal resonator corresponding to the number of resonance frequencies, resulting in the miniaturization of equipment that requires multiple frequencies. And making it difficult to lower prices.

Also, in the case of a crystal oscillator, a temperature compensator such as a temperature compensation circuit or a thermostat is incorporated in the crystal oscillator as in the case of the above-described crystal resonator. A control circuit is required, the number of circuit components is large, and adjustment work is required, resulting in a problem that the cost is increased. On the other hand, in the latter method,
There is a problem that the volume occupied by the thermostat is large and the current consumption is further increased.

In addition, an analog temperature-compensated crystal oscillator using a thermistor or the like requires separate compensating circuits for high temperature and low temperature, requires a large number of circuit parts, complicates adjustment work, and increases cost. Had.

On the other hand, in the digital temperature compensation crystal oscillator,
The temperature sensor and the crystal unit for oscillation are provided separately, and appropriate temperature compensation cannot be performed unless the temperature difference caused by the difference in thermal time constant or the difference in installation location between the two is suppressed. There have been problems such as the necessity of a memory having a large capacity and an increase in adjustment cost.

Further, in order to suppress the temperature difference between the temperature sensor and the quartz oscillator, a method of extracting a fundamental wave and a higher-order overtone or sub-vibration with a single quartz oscillator is based on a method of extracting the fundamental wave and the higher order over a wide temperature range. It is necessary to excite each overtone or sub-vibration independently, selectively and stably.To do so, it is necessary to determine the crystal oscillator design and the bias and feedback capacitance of the handling circuit very strictly. In some cases, it is necessary to compensate the temperature of the bias and feedback capacitance of the oscillation circuit, which has a problem that the circuit scale is large, very complicated, and difficult to manufacture.

Further, the crystal filter has a problem that the stability of the frequency-temperature characteristic is low and a problem that it is difficult to reduce the size because of the planar configuration.

In view of the above problems, the present invention provides a quartz crystal resonator in which at least two quartz pieces having different frequency-temperature characteristics are directly joined without any inclusion, and a resonance frequency-temperature characteristic is superior to that of the prior art. A crystal unit that can easily configure a structure to increase Q, a crystal unit that can take out multiple vibrations with an arbitrary resonance frequency and temperature characteristics by itself, and an oscillation frequency-
To provide a crystal oscillator with excellent temperature characteristics, a low-cost temperature-compensated crystal oscillator with a small number of components and high-precision temperature compensation, a crystal filter with stable frequency-temperature characteristics, and a small crystal filter. Aim.

[0032]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems , the method for directly joining quartz pieces according to the present invention employs a desired cutting method.
At least two crystals with different angles and desired thickness
The joint surfaces of the pieces are mirror-polished, and the cleaning solution is sufficient.
To remove any contaminants and heat dry.
To remove the water molecules that are hydrogen bonded to the bonding surface.
And smoothed and flattened and terminated by hydroxyl group
After that, by contacting without inclusions, the hydroxyl group on the bonding surface
After joining by the bonding force acting between
Heat treatment within the temperature range that does not cause phase transition, resulting in stronger bonding
It is directly joined by force .

Further, the crystal resonator of the present invention has a frequency-temperature
At least two quartz pieces with different degree characteristics without inclusions
2. The method of claim 1, wherein the quartz pieces are laminated in the thickness direction.
And the thickness of the bonded crystal blank
And an excitation electrode that is installed facing the
When a field is added, the bonded quartz pieces vibrate .

Further, the crystal oscillator of the present invention is characterized in that
The above-described quartz resonator is used as a resonance element .

Further, crystal filter of the present invention, according to claim 1
A small amount of quartz chips joined by the
At least two pairs of counter electrodes are installed facing each other in the thickness direction
And input an electric signal from one of the pair of the counter electrodes.
And a specific frequency component from the other pair of counter electrodes.
It outputs an air signal .

[0036]

According to the present invention, a bonded crystal piece in which at least two crystal pieces having different frequency-temperature characteristics are directly bonded without inclusions is used. (1) The directly bonded crystal pieces are integrally vibrated. Therefore, the resonance frequency-temperature characteristics of the respective crystal blanks cancel each other, and a crystal resonator and a crystal filter that are stable in temperature can be realized.

(2) By the direct bonding, a three-dimensional structure in which the thickness of the vibrating portion and the thickness of the supporting portion are different from each other can be realized easily and in a short time, and a high-Q crystal resonator can be realized.

(3) Since the directly bonded crystal pieces vibrate together, a crystal resonator which can take out a plurality of vibrations having an arbitrary resonance frequency and temperature characteristics can be realized.

(4) Since a crystal oscillator that is stable in temperature can be used, a crystal oscillator having excellent frequency-temperature characteristics can be realized.

[0040]

[0041]

[0042] (5) by direct bonding, resonance can Ru is sterically bound, small crystal filter can be realized.

[0043]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the present invention, different frequencies-
Since at least two quartz pieces having temperature characteristics are directly joined without any inclusion, a specific example of the joining method will be described first.

FIG. 1 shows a first example of a method for directly joining quartz pieces. The direct bonding procedure for quartz is (1) mirror polishing, (2) cleaning, (3) drying, (4) contact, (5)
It consists of each step of heat treatment.

The details will be described below with reference to the flowchart of FIG.

First, as a mirror polishing step (1), the surfaces of a plurality of quartz pieces are made smooth and flat with irregularities of about several hundred angstroms.

Further, in the cleaning step (2), a wet scrub cleaning using a detergent and a cleaning using isopropyl alcohol are performed in order to remove dirt and abrasive particles adhered in the mirror polishing step (1). Further, cleaning is performed using a mixed solution of sulfuric acid and hydrogen peroxide solution. In this state, the crystal surface is in a state in which hydroxyl groups are bonded to dangling bonds of crystal surface atoms, and these hydroxyl groups are hydrogen-bonded to surrounding water molecules.

Next, in the drying step (3), in order to remove water molecules that are hydrogen-bonded to the surface of the crystal blank, the crystal blank is heated and dried in an environment where foreign matter such as dust does not adhere. For example, 30
Hold at 0 ° C. for 1 hour. The surface of the crystal blank after the above procedure is terminated with a hydroxyl group dangling bonded to the surface atom of the crystal blank.

Next, in the contacting step (4), when the crystal blanks having the above-mentioned surface condition are brought into contact with each other, the hydroxyl group bonded to the surface of one of the crystal blanks and the crystal blank facing the same are contacted on the contact surface. Hydroxyl groups bonded to the surface are hydrogen-bonded to each other, and this hydrogen bonding provides an initial weak bonding state between the quartz pieces without any inclusion such as an adhesive.

Further, in the heat treatment step (5), for the purpose of improving the mechanical and electrical properties, the crystal blanks that have been initially bonded to each other are subjected to a heat treatment within a temperature range in which the crystal crystals do not undergo phase transition. For example, 500 ° C under atmospheric pressure
It should be done in. Due to the heat treatment, the hydroxyl groups that have contributed to the initial bonding of the crystal pieces are dehydrated and condensed, some are released to the outside through the bonding interface of the crystal pieces, and some are diffused into the crystal. The pieces are firmly joined directly.

It should be noted that the introduction of a drying step to remove water molecules before contacting the crystal piece prevents the water molecules from undergoing a elimination reaction in the subsequent heat treatment step, thereby preventing gasification. This is because a direct bonding state can be obtained and the yield of the direct bonding of crystal is improved.

According to the above method, the quartz pieces can be directly joined mechanically and firmly. Further, when elastic vibration is electrically excited in the directly bonded crystal blank, the elastic vibration continuously propagates at the directly bonded interface, and the directly bonded crystal blank integrally performs elastic vibration. For example, the resonance frequency in the case where two crystal blanks whose resonance frequency in the thickness-shear vibration mode is expressed by (Equation 1) is directly joined is expressed by (Equation 2).
If the same crystal piece is directly joined, 2
It has the same resonance frequency as one crystal piece having a thickness obtained by combining the crystal pieces.

[0053]

(Equation 1)

[0054]

(Equation 2)

Further, since the directly bonded interface does not hinder elastic vibration, the Q of the directly bonded crystal piece does not deteriorate.

FIG. 2 shows a second example of a method for directly joining crystal blanks. The direct bonding procedure for quartz is (1) mirror polishing, (2) cleaning, (3) drying, (4) contact, (5)
It consists of each step of heat treatment.

Basic Procedure (Steps (1) to (5))
And the effect is the same as in the first example,
In the second example, in the cleaning step (2), by using drying using isopropyl alcohol as preliminary drying before the heating and drying step (3), foreign substances such as dust adhering to the crystal surface after cleaning are removed. Can be reduced.

FIG. 3 shows a third example of a method for directly joining crystal blanks. The direct bonding procedure for quartz is (1) mirror polishing, (2) cleaning, (3) drying, (4) contact, (5)
It consists of each step of heat treatment.

The basic procedure and effects of the third example are the same as those of the first example, but here,
In the cleaning step (2), by performing cleaning with hydrogen fluoride water or ammonium fluoride water, the quartz surface can be chemically polished, and a cleaner surface can be obtained.

In each of the first, second, and third examples, a step of holding in a dry atmosphere for a long time may be used instead of heating and drying.

FIG. 4 shows a first embodiment of the present invention (the first embodiment).
(A) is a side view, (b) is a plan view of (a) viewed from above, and (c) is a diagram showing an example of a resonance frequency-temperature characteristic of a bonded quartz piece. is there. 4A and 4B, 101 and 102
Is a crystal blank, 103 is an excitation electrode, and 104 is a bonded crystal blank. P is the normal to the plate surfaces of both the crystal blanks 101 and 102, and X ₁ , Y ₁ and Z ₁ are the crystal blanks 10 and 10.
The crystal axis 1, X ₂ , Y ₂ and Z ₂ are the crystal axes of the crystal blank 102, θ is the angle between P and Z ₁ , and φ is the angle between P and Z ₂ .

[0062] crystal element 101 and 102, come together directly bonded by a direct bonding method according to the first to third examples as X ₁ and X ₂ are identical, laminated crystal blank 1
04. In addition, the excitation electrodes 103 are opposed to each other via a bonded quartz piece 104.

The operation of the thus configured quartz oscillator will be described below.

The crystal blanks 101 and 102 are
When an electric field (electric field in the P direction) is applied to _No. 3, thickness shear strain is generated, and the respective resonance frequencies f ₁ and f ₂ are expressed by (Equation 1) using the respective thicknesses and elastic constants.

Further, since the quartz pieces 101 and 102 are directly joined, elastic vibration is continuous at the joining surface. At this time, the resonance frequency f of the bonded quartz piece 104 is expressed by (Equation 2). Therefore, bonded crystal blank 1
The temperature characteristic of 04 is the resonance frequency-temperature characteristic of the crystal blanks 101 and 102 (that is, the cutout angles θ and φ).
And the thickness ratio. For example, the thickness ratio between the crystal blank 101 and the crystal blank 102 is 5: 1, and θ and φ are 55.01 ° (AT cut) and 145.00, respectively.
If ゜ (BT cut), as shown in FIG.
In the temperature range of 0 to 80 ° C. (horizontal axis), the frequency deviation (vertical axis) has a frequency stability of ± 1.0 ppm.

As described above, according to the first embodiment, the excitation electrodes are opposed to each other via the bonded crystal piece in which two crystal pieces having different frequency-temperature characteristics are directly bonded without any inclusion. 4C, the resonance frequency-temperature characteristics of each crystal blank cancel each other out, and FIG.
As shown in (1), a crystal resonator having a stable resonance frequency over a wide temperature range can be realized.

(Second Embodiment) FIGS. 5A and 5B show a crystal unit according to a second embodiment of the present invention, wherein FIG. 5A is a side view, and FIG. FIG. In FIG. 5, reference numerals 111, 112, and 113 denote crystal blanks, 114 denotes an excitation electrode, and 115 denotes an excitation electrode.
Is a bonded crystal blank. P is crystal blank 111, 112
And 113 are the normals of all the plate surfaces. X ₁ , Y
₁ and Z ₁ are the product axes of the crystal blank 111, X ₂ , Y ₂ and Z ₂ are the crystal axes of the crystal blank 112, X ₃ , Y ₃ and Z ₃
Is the crystal axis of the crystal piece 113, and θ, φ, and ξ are the angles formed by P and Z ₁ , P and Z _2, and P and Z ₃ , respectively. The crystal blanks 111, 112 and 113 are directly joined so that X ₁ , X ₂ and X ₃ coincide with each other to be integrated,
A bonded crystal piece 115 is provided. In addition, the excitation electrodes 114 are opposed to each other with a bonded crystal piece 115 interposed therebetween.

The resonance frequency-temperature characteristics of the quartz resonator having the above-described structure are the same as those of the first embodiment.
Depending on the thickness ratio of 1, 112 and 113 and the respective cutout angles θ, φ and ξ, desired values can be obtained. In contrast to the first embodiment, when three crystal pieces are directly bonded to form a bonded crystal piece,
It is possible to realize a bonded crystal resonator having a resonance frequency-temperature characteristic with higher stability.

(Third Embodiment) FIG. 6 shows a third embodiment of the present invention (the invention according to claim 2).
3A is a side view, and FIG. 3B is a plan view of FIG. 3A as viewed from above. In FIG. 6, reference numerals 121 and 122 denote crystal blanks, reference numeral 123 denotes an excitation electrode, and reference numeral 124 denotes a bonded crystal blank. Crystal piece 1
Each of the surfaces 21 and 122 has a thicker central portion and a smaller thickness (convex process) toward the ends. Quartz pieces 121 and 122 are the first embodiment (FIG. 4).
In the crystal axis relation and the thickness ratio as shown in the above, the non-convex-processed side is directly bonded and integrated to form a bonded quartz piece 124. Also, the excitation electrode 1
The reference numeral 23 is provided to face each other via a bonded crystal piece 124.

With the above configuration, the resonance frequency can be stably maintained over a wide temperature range as in the first embodiment, and at the same time, the center portion of the bonded crystal piece 124 is thicker toward the end portion. As a result, the effect of confining the elastic vibration in the central portion is obtained, and a high-Q crystal resonator can be realized.

In the third embodiment, the quartz piece 1
The same result can be obtained by using a crystal piece 21 or 122 which has been subjected to double-sided convex processing or processing in which the corners of one or both ends are cut off (bevel processing).

In each of the above-described first to third embodiments of the present invention, the relationship among the cut-out angle, the thickness, the number, and the crystal axes of the crystal pieces directly bonded to form the bonded crystal piece is not limited. There is no limitation, and it can be set so that the bonded quartz piece has a desired resonance frequency-temperature characteristic.

Also, in a vibration mode other than the thickness shear vibration, a desired temperature characteristic can be realized by using the bonded quartz pieces as shown in the first and second embodiments of the present invention.

(Fourth to Seventh Embodiments) FIGS. 7 to 10 show crystal oscillators according to the fourth to seventh embodiments of the present invention, respectively. FIG. 2B is a plan view of FIG.

In the fourth embodiment shown in FIG. 7, 131 and 132 are crystal blanks, 133 is an excitation electrode, 134 and 1
Reference numeral 35 denotes a supporting portion, 136 denotes a vibrating portion, and 137 denotes a bonded crystal piece. The crystal blanks 131 and 132 are
At 36, they are directly bonded and integrated to form a bonded crystal piece 137. In addition, the excitation electrodes 133 are opposed to each other via the vibrating section 136.

In the fifth embodiment shown in FIG. 8, 141 is a crystal blank, 142 is a crystal blank larger than the crystal blank 141, 14
3 is an excitation electrode, 144 and 145 are support parts, 146 is a vibration part, and 147 is a bonded crystal piece. The crystal blanks 141 and 142 are directly bonded and integrated so that their centers substantially coincide with each other to form a bonded crystal blank 147. In addition, the excitation electrode 143 is opposed to the vibration electrode 146.

In the sixth embodiment shown in FIG.
52 and 153 are crystal blanks, 154 is an excitation electrode, 155
Reference numerals 156 and 156 denote supporting portions, 157 denotes a vibrating portion, and 158
Is a bonded crystal blank. The crystal blanks 152 and 153 are smaller than the crystal blank 151, and are directly joined so that their centers substantially coincide with each other in the bonding order shown in FIG. Further, the excitation electrodes 154 are opposed to each other via the vibrating section 157.

In the seventh embodiment shown in FIG.
162 and 163 are crystal blanks, 164 is an excitation electrode, 16
5 and 166 are support parts, 167 is a vibration part, and 16
8 is a bonded crystal blank. The crystal blanks 161, 162 and 163 are directly joined in the joining sequence shown in FIG. Further, the excitation electrodes 164 are opposed to each other via the vibrating section 167.

In each of the fourth to seventh embodiments configured as described above, when an electric field is applied to the excitation electrode, the vibrating portion generates a thickness shear strain, and as shown in (Equation 1) and (Equation 2). The resonance frequency of the vibrating part is determined by the thickness and elastic constant of each crystal element. The elastic vibration generated in the vibrating part tries to transmit to the end of the bonded crystal piece through the supporting part, but since the supporting part is configured to be thinner than the vibrating part, the elastic vibration suddenly occurs in the supporting part. Decay.

As described above, according to each of the fourth to seventh embodiments, at least two crystal pieces are directly joined to form a bonded crystal piece having a thick central portion. Since the excitation electrode is provided through the intermediary, elastic vibration can be confined, and a high-Q crystal resonator can be easily realized.

(Eighth Embodiment) FIGS. 11A and 11B show a crystal resonator according to an eighth embodiment of the present invention (the invention according to claim 3), wherein FIG. 11A is a side view, and FIG. FIG. 3 is a plan view of FIG. FIG.
In FIG. 1, 171 is a crystal blank having a hole 171a in the center, 172 is a crystal blank, and 173 is an excitation electrode.
Is a bonded crystal blank. The crystal blanks 171 and 172 are directly bonded and integrated to form a bonded crystal blank 174. The excitation electrode 173 is located at the center of the crystal blank 1.
The vibrating portions 177 that are not bonded to each other are mounted opposite to each other via the crystal blank 172. Further, supporting portions 175 and 176 are formed in a region where the crystal blanks 171 and 172 are directly joined.

In the eighth embodiment configured as described above, when an electric field is applied to the excitation electrode 173,
Causes thickness shear strain, and the resonance frequency of the vibrating part is determined by the thickness and the elastic constant as shown in (Equation 1) and (Equation 2). The elastic vibration generated in the vibrating portion 177 is to be transmitted to the end of the bonded crystal piece 174, but the thickness of the supporting portions 175 and 176 is larger than that of the vibrating portion 177.
In other words, since the central portion is formed of a bonded crystal piece that is thinner than the peripheral portion, the elastic vibration can be confined in the vibrating portion 177.

As described above, according to the eighth embodiment,
At least two crystal pieces are directly bonded to form a thin bonded crystal piece at the center, and the excitation electrode is provided through the thin part at the center, so that elastic vibration can be confined, The Q crystal resonator can be easily realized.

In each of the fourth to eighth embodiments of the present invention, there is no limitation on the number and thickness of the crystal pieces directly joined, and the thickness of the vibrating portion is larger than the thickness of the supporting portion. The same effect can be obtained if it is configured to be thin.

In each of the fourth to eighth embodiments of the present invention, for example, a crystal piece having a cutout angle and a thickness as shown in each of the first to third embodiments of the present invention is used.
Further, if the vibrating portion is formed by directly joining the crystal axes in relation to the crystal axis, it is possible to realize a high-Q crystal resonator having stable resonance frequency-temperature characteristics.

In each of the fourth to eighth embodiments of the present invention, the shape of the vibrating portion and the supporting portion is not limited at all, and the shape of the quartz piece is the disk shape shown in the embodiment of the present invention. Any shape such as a square plate shape can be used without particularity.

In each of the first to eighth embodiments of the present invention, the third embodiment of the present invention (FIG. 6)
A quartz piece which has been subjected to convex or beveled processing on both sides or one side as shown in the above may be used, or may be subjected to convex processing (the central part of the quartz piece is processed thicker than the peripheral part) or bevel processing (crystal piece). (A single-sided or double-sided surface) and a flat-plated crystal piece may be combined.

(Ninth to Eleventh Embodiments) FIGS. 12, 13 and 14 show a ninth embodiment of the present invention, respectively.
It is a side view showing the structure of the crystal unit in the eleventh to eleventh embodiments (invention of claim 4).

In the ninth embodiment shown in FIG. 12, reference numerals 181 and 182 denote crystal blanks having different thicknesses, 183 denotes a direct bonding portion, 184 and 185 denote excitation electrodes, and 186 denotes a bonded crystal blank. The crystal blanks 181 and 182 are directly bonded to each other to be integrated, and the bonded crystal blank 186 is attached.
Is formed. The bonded crystal blank 186 is the crystal blank 18
1 and 182 in combination with the thickness of the direct bonding portion 183 and the thickness of only the crystal blank 181 (the left excitation electrode 1
85 part). The excitation electrode 184 is installed to face directly via the joint 183, and the excitation electrode 185
Are opposed to each other via a crystal blank 181.

In the tenth embodiment shown in FIG.
Reference numerals 191, 192 and 193 denote crystal blanks having different thicknesses, reference numeral 194 denotes a direct bonding portion, reference numerals 195 and 196 denote excitation electrodes, and reference numeral 197 denotes a bonded crystal blank. The crystal blanks 191, 192 and 193 are directly bonded to each other and integrated to form a bonded crystal blank 197. The bonded crystal blank 197 is composed of a direct bonding portion 194 having a thickness obtained by combining the crystal blanks 191, 192 and 193 and the crystal blank 19.
It has a portion having only one thickness (the portion of the excitation electrode 195 on the left side in the figure). The excitation electrode 196 is directly connected to the joint 194.
The excitation electrodes 195 are opposed to each other via a crystal blank 191.

In each of the ninth and tenth embodiments configured as described above, when an electric field is applied to the excitation electrode, a thickness shear strain occurs, and the crystal piece between the excitation electrodes 185 and 195 becomes (Equation 1). Vibrates at the resonance frequency represented by Further, as described in the first embodiment (FIG. 4), the direct joint vibrates at the resonance frequency represented by (Equation 2).

As described above, according to the ninth and tenth embodiments, two or three crystal blanks are directly joined to form bonded crystal blanks 186 and 197 having two thicknesses, respectively. Since the two sets of excitation electrodes are opposed to each other with a thickness of 2 mm, a crystal resonator having two arbitrary resonance frequencies can be easily realized.

FIG. 14 is a side view showing a structure of a crystal resonator according to an eleventh embodiment of the present invention. In FIG. 14, reference numerals 201 and 202 denote crystal blanks having different thicknesses.
Is a direct bonding portion, 204, 205 and 206 are excitation electrodes, and 207 is a bonded crystal blank. Crystal piece 20
1 and 202 are directly bonded to each other to be integrated, and form a bonded crystal piece 207. The bonded crystal piece 207 includes a direct bonding portion 203 having a thickness obtained by combining the crystal pieces 201 and 202 and a portion having a thickness only of the crystal pieces 201 and 202 (the left and right excitation electrodes 205 and 20 in the drawing).
6 part). The excitation electrodes 204 are opposed to each other via a direct bonding portion 203, and the excitation electrodes 205 and 206 are opposed to each other via crystal blanks 201 and 202, respectively.

As described above, according to the eleventh embodiment,
In the same manner as in the ninth and tenth embodiments, any three
A crystal resonator having two resonance frequencies can be realized.

Further, in each of the ninth to eleventh embodiments shown in FIGS.
191 and 201 and 202 are bonded crystal blanks 18.
6, 197 and 207 may be constituted by directly bonded bonded quartz pieces, and a quartz resonator having any three resonance frequencies can be realized in the same manner as described above.

(Twelfth to Fourteenth Embodiments) FIGS. 15, 16 and 17 show a first embodiment of the present invention, respectively.
It is a side view showing the structure of the crystal oscillator in the 2nd-14th examples (the invention of Claim 5).

In the twelfth embodiment shown in FIG.
Reference numerals 1, 212 and 213 denote crystal blanks having different thicknesses, and 211 and 213 have the same thickness. 216 and 217 are excitation electrodes, 214 and 215 are direct bonding portions, and 218 is a bonded crystal blank. The crystal blank 211 is directly bonded to the crystal blanks 212 and 213 to be integrated,
A bonded crystal piece 218 is formed. The bonded crystal blank 218 has a direct bonding portion 214 having a thickness combining the crystal blanks 211 and 212 and a direct bonding portion 215 having a thickness combining the crystal blanks 211 and 213. It has a portion (central portion in the figure) having a thickness of only the crystal blank 211. Excitation electrode 216
Are disposed opposite each other via a direct joint 214, and the excitation electrodes 217 are disposed opposite each other via a direct joint 215.

In the thirteenth embodiment shown in FIG.
1, 222, 223 and 224 are crystal blanks having different thicknesses. 227 and 228 are excitation electrodes;
Reference numerals 5 and 226 denote direct bonding portions, and 229 denotes a bonded crystal blank. Crystal blank 221 and crystal blanks 222, 223 and 22
4 is directly bonded and integrated, and a bonded crystal piece 229 is attached.
Is formed. The bonded crystal blank 229 is the crystal blank 2
A direct bonding portion 225 having a thickness obtained by combining 21, 22, and 223 and a direct bonding portion 226 having a thickness obtained by combining the crystal pieces 221 and 224 are further provided.
26, a portion having a thickness of only the crystal blank 221 is provided. The excitation electrodes 227 are opposed to each other via a direct joint 225, and the excitation electrodes 228 are opposed to each other via a direct joint 226.

As described above, according to the twelfth and thirteenth embodiments, the ninth and tenth embodiments (FIG. 12, FIG.
As in FIG. 13), a crystal resonator having any two resonance frequencies can be obtained, and a region thinner than the two direct junctions can be provided between the two direct junctions. The elastic vibration generated at each of the two direct joining portions can be confined inside, and the isolation between the two elastic vibrations can be increased.

FIG. 17 is a side view showing the structure of a quartz oscillator according to a fourteenth embodiment of the present invention. In FIG. 17, reference numerals 231, 232 and 233 denote crystal blanks having different thicknesses, reference numerals 234, 235 and 236 denote direct bonding portions, reference numerals 237 and 238 denote excitation electrodes, and reference numeral 239 denotes a bonded crystal blank. The crystal blank 231 and the crystal blanks 232 and 233 are
Directly bonded together to form a single piece, bonded crystal blank 2
39 are formed. The bonded crystal blank 239 is a direct bonding portion 23 having a thickness obtained by combining the crystal blanks 231 and 232.
4, a direct bonding part 235 having a thickness combining the crystal pieces 231 and 233 and a direct bonding part 236 having a thickness combining the crystal pieces 231, 232 and 233. The excitation electrodes 237 are opposed to each other via a direct joint 234, and the excitation electrodes 238 are opposed to each other via a direct joint 235.

As described above, according to the fourteenth embodiment,
As in the ninth and tenth embodiments (FIGS. 12 and 13), it is possible to obtain a quartz oscillator having any two resonance frequencies. Since the direct bonding portion 236 thicker than the two direct bonding portions can be provided, the elastic vibrations generated in the direct bonding portions 234 and 235 can be confined inside, and the isolation between the two elastic vibrations can be increased. it can.

The ninth, tenth, and first aspects of the present invention
In each of the first, twelfth, thirteenth and fourteenth embodiments,
There is no limitation on the number of crystal pieces, the cutting angle, the thickness, and the crystal axis relation at the time of direct joining. For example, as shown in the first, second and third embodiments of the present invention,
Each crystal blank or bonded crystal blank can be freely set so as to have a desired resonance frequency-temperature characteristic.

There is no limitation on the number of sets of excitation electrodes.
It can be set to obtain any number of desired frequencies.

The shape of the crystal blank and the shape of the excitation electrode are not limited at all, and may be arbitrarily set, such as a circle or a square. Further, a convex-cut crystal piece as shown in the third embodiment can be used as the crystal piece.

In the first to fourteenth embodiments of the present invention, the number, pattern shape, composition and thickness of the excitation electrodes are not limited at all.

(Fifteenth Embodiment) FIG. 18 is a circuit diagram of a crystal oscillator according to a fifteenth embodiment (the invention according to claim 6) of the present invention. In FIG. 18, reference numeral 241 denotes a quartz oscillator as described in each of the first to eighth embodiments (FIGS. 4 to 11) of the present invention, and at least two quartz pieces having different frequency-temperature characteristics. This is a crystal resonator having a stable resonance frequency over a wide temperature range, with a configuration in which excitation electrodes are opposed to each other via a bonded crystal piece directly bonded without inclusions. 242 is an oscillation circuit, and 243 is an output terminal.

In the crystal oscillator configured as described above,
In the vicinity of the resonance frequency of the crystal oscillator 241, the oscillation conditions of the oscillation circuit 242 and the crystal oscillator 241 are satisfied, and an oscillation signal is output from the output terminal 243. Here, the output frequency-temperature characteristic is substantially determined by the resonance frequency-temperature characteristic of the crystal unit 241.

As described above, according to the fifteenth embodiment,
Since a crystal resonator which is stable against temperature as shown in each of the first to eighth embodiments is used as a resonance element,
A crystal oscillator having a stable output frequency over a wide temperature range can be realized.

(Sixteenth Embodiment) FIG. 19 is a circuit diagram of an analog temperature-compensated crystal oscillator according to a sixteenth embodiment of the present invention (the invention according to claim 7). In FIG. 19, reference numeral 251 denotes a quartz oscillator as described in each of the first to eighth embodiments (FIGS. 4 to 11) of the present invention, and at least two quartz pieces having different frequency-temperature characteristics. This is a crystal resonator having a stable resonance frequency over a wide temperature range, with a configuration in which excitation electrodes are opposed to each other via a bonded crystal piece directly bonded without inclusions. 252 is a temperature compensation circuit, 253 is an oscillation circuit, and 254 is an output terminal.
Is a circuit composed of a temperature-sensitive element, a resistance element and a capacitance element, and the reactance of which changes with temperature.

In the analog temperature-compensated crystal oscillator configured as described above, the change in the reactance (resonance frequency) of the crystal resonator 251 due to the temperature is compensated by the temperature compensation circuit 252 to stabilize the output frequency-temperature characteristics. ing. By the way, as shown in FIG. 4C, the resonance frequency-temperature characteristic of the crystal unit 251 can obtain a frequency stability of ± 1.0 ppm in a temperature range from 10 ° C. to 80 ° C. When constructing a temperature-compensated crystal oscillator for a body communication device, the temperature compensation is required in a temperature range of -30C to 10C. Therefore,
Conventionally, the temperature compensating circuits independently required for the high temperature and the low temperature need only be the temperature compensating circuits for the low temperature, and the circuit scale of the temperature compensating circuit 252 can be reduced to half.

As described above, according to the present embodiment, by using a crystal resonator having a stable resonance frequency over a wide temperature range as shown in each of the first to eighth embodiments of the present invention, Since the scale of the compensation circuit can be reduced by half and the manufacturing process and the adjustment process can be simplified, a small and low-cost analog temperature-compensated crystal oscillator can be realized.

In the sixteenth embodiment of the present invention,
A thermistor, a diode, or the like can be used as the temperature sensing element, and a capacitor, a variable capacitance diode, or the like can be used as the capacitance element.

(17th to 19th Embodiments) FIGS. 20 to 22 are block diagrams showing the configuration of a digital temperature compensated crystal oscillator according to the 17th to 19th embodiments of the present invention.

In the seventeenth embodiment (invention 8) of FIG. 20, from the left block, 266 is a temperature sensor, 265 is an A / D converter, 264 is a storage device, 263
Is a variable reactance circuit controlled by a digital signal, and 262 is an oscillation circuit. Reference numeral 261 denotes a quartz oscillator as described in each of the first to eighth embodiments of the present invention, which is a bonded unit in which at least two quartz pieces having different frequency-temperature characteristics are directly joined without any inclusion. With a configuration in which the excitation electrodes are opposed to each other via a crystal blank, the crystal resonator has a stable resonance frequency over a wide temperature range. 26
7 is a crystal oscillator 261, a variable reactance circuit 263
And a digitally controlled crystal oscillator including an oscillation circuit 262.

In the eighteenth embodiment (the ninth aspect of the present invention) shown in FIG. 21, reference numeral 273 denotes a temperature sensor, and 274 denotes an A / D.
A converter 275 is a storage device, 276 is a programmable frequency divider, 272 is a crystal oscillator, and 271 is the first of the present invention.
As shown in each of the eighth to eighth embodiments, a configuration in which the excitation electrodes are opposed to each other through a bonded crystal piece in which at least two crystal pieces having different frequency-temperature characteristics are directly bonded without any inclusion, The crystal oscillator has a stable resonance frequency over a wide temperature range, and serves as a resonance element of the crystal oscillator 272.

In the nineteenth embodiment shown in FIG.
And 283 are crystal oscillators, 284 is a frequency counter,
285 is a storage device, 286 is a programmable frequency divider, 2
Numeral 81 denotes an excitation via a bonded crystal piece in which at least two crystal pieces having different frequency-temperature characteristics are directly bonded without any inclusion as shown in the first to eighth embodiments of the present invention. Due to the configuration in which the electrodes are opposed to each other, the resonator is a crystal resonator having a stable resonance frequency over a wide temperature range, and serves as a resonance element of the crystal oscillator 282. Also,
The crystal oscillator 283 is a crystal oscillator used as a temperature sensor, and is configured using a crystal resonator having a resonance frequency-temperature characteristic that facilitates temperature detection.

In the digital temperature compensated crystal oscillator configured as described above, the storage devices 264, 275 and 285
The output signal of the A / D converter 265 or 274 or the frequency counter 284 and the variable reactance circuit 2
63, or a programmable frequency divider 276 or 2
Data corresponding to the 86 control signals is stored in advance. As a result, the reactance of the variable reactance circuit or the division ratio of the programmable frequency divider changes in response to the temperature change, and the oscillation output frequency is stabilized by compensating the resonance frequency-temperature characteristic of the crystal resonator.

The characteristics of the quartz oscillators 261, 271 and 281 shown in FIGS. 20, 21 and 22 are within ± 1.0 ppm in the temperature range from 10 ° C. to 80 ° C. as shown in FIG. Since the frequency stability can be obtained, when configuring a temperature-compensated crystal oscillator for a mobile communication device such as a mobile phone, temperature compensation is required only by -3.
The temperature range is from 0 ° C. to 10 ° C., and the temperature range is greatly reduced to approximately ／ of the conventional temperature range.

As described above, according to the seventeenth to nineteenth embodiments of the present invention, a crystal having a stable resonance frequency over a wide temperature range as shown in the first to eighth embodiments of the present invention. Since the vibrator is used, the temperature range to be compensated is greatly reduced, the capacity of the storage device and the number of bits of the A / D converter can be reduced, and the manufacturing and adjustment steps can be simplified. A low-cost digital temperature-compensated crystal oscillator with low current consumption can be realized. Further, the temperature sensor only needs to be able to detect the temperature at a low temperature, and the degree of freedom of elements and circuits is increased.

In each of the seventeenth and nineteenth embodiments of the present invention, as the temperature sensor, an element or a circuit using a thermistor, a diode, or the like, whose potential difference or current value changes depending on the temperature can be used. Further, a crystal oscillator can be used as the temperature sensor. When a crystal oscillator is used, a frequency counter can be used as the A / D converter.

In the seventeenth embodiment of the present invention,
As the variable reactance circuit, for example, using a D / A converter and a variable capacitance diode, the output voltage of the D / A converter is applied to the variable capacitance diode, or the capacitance value is directly changed by switching using a digital signal. A method or the like can be used.

In the nineteenth embodiment of the present invention,
The crystal unit 281 and the crystal unit used in the crystal oscillator 283 are integrated, for example, by the configurations shown in the ninth, tenth, twelfth, thirteenth, and fourteenth embodiments of the present invention. And can be configured.

The fifteenth, sixteenth, and first aspects of the present invention
In the seventh, eighteenth, and nineteenth embodiments, the quartz oscillators 241, 251, 261 and 27 shown in FIGS.
It is not necessary to use a quartz oscillator having a resonance frequency-temperature characteristic as shown in FIG. 4C, and a stable resonance frequency in a desired temperature range is used for 1 and 281.
The number of the crystal pieces directly joined, the cutout angle, the thickness, and the relationship between the crystal axes can be arbitrarily set so that the temperature characteristics can be obtained.

20th to 23rd Embodiment FIGS. 23 to 26 are block diagrams showing the configuration of a digital temperature-compensated crystal oscillator according to the twentieth to twenty-third embodiments (invention 10) of the present invention. FIG.

In the twentieth embodiment shown in FIG.
Is a quartz crystal unit which can take out two vibrations having arbitrary resonance frequency and temperature characteristics by itself as shown in the ninth embodiment (FIG. 12) of the present invention. 292 and 293 are two first and second vibrating parts formed on the crystal unit 291. Reference numeral 294 denotes a first oscillation circuit, 295 denotes a variable reactance circuit for digital signal control, and 296 denotes a digitally controlled crystal oscillator including a first vibrator 292, a first oscillation circuit 294, and a variable reactance circuit 295. 297 is a storage device, and 298 is an A / D converter. Reference numeral 299 denotes a second oscillation circuit, and reference numeral 300 denotes a temperature sensor including the second vibration section 293 and the second oscillation circuit 299. Here, the quartz oscillator 291 is so arranged that the second vibrating section 293 has a resonance frequency-temperature characteristic that allows easy temperature detection, and the first vibrating section 292 has a stable resonance frequency-temperature characteristic. The cutout angle, thickness, and crystal axis relationship are set for the two crystal pieces that make up,
Directly joined.

In the twenty-first embodiment shown in FIG.
Is a quartz oscillator which can take out two vibrations having arbitrary resonance frequency and temperature characteristics by itself as shown in the ninth embodiment (FIG. 12) of the present invention. 302 and 30
Numeral 3 denotes two first and second elements formed on the crystal unit 301.
Vibrating part. Reference numeral 304 denotes a first vibration unit 302 and a first
Is a digitally controlled crystal oscillator composed of an oscillation circuit 294 and a variable reactance circuit 295, and 305 is a temperature sensor composed of a second vibration section 303 and a second oscillation circuit 299. Here, the second vibrating section 303 has a resonance frequency-temperature characteristic such that the temperature can be easily detected, and the first vibration section 303 has the first frequency characteristic.
The two pieces of crystal constituting the crystal unit 301 are set to have a cut-out angle, a thickness, and a crystal axis relationship, and are directly joined so that the vibrating part 302 has stable resonance frequency-temperature characteristics.

In the twenty-second embodiment shown in FIG.
Is a quartz oscillator which can take out two vibrations having an arbitrary resonance frequency and temperature characteristics by itself as shown in the tenth embodiment (FIG. 13) of the present invention. 312 and 313
Are two first and second vibrating portions formed on the quartz oscillator 311. Reference numeral 314 denotes a digitally controlled crystal oscillator including a first vibrating unit 312, a first oscillation circuit 294, and a variable reactance circuit 295. Reference numeral 315 denotes a temperature sensor including a second vibrating unit 313 and a second oscillation circuit 299. . Here, the crystal resonator 311 is set so that the second vibrating section 313 has a resonance frequency-temperature characteristic that allows easy temperature detection, and the first vibrating section 312 has a stable resonance frequency-temperature characteristic. The three crystal blanks that are configured are set directly at the cutout angle, thickness, and crystal axis relationship, and are directly joined.

In the twenty-third embodiment shown in FIG.
Is a quartz oscillator which can take out two vibrations having an arbitrary resonance frequency and temperature characteristics by itself as shown in the twelfth embodiment (FIG. 15) of the present invention. 322 and 323
Are two first and second vibrating parts formed on the crystal unit 321. Reference numeral 324 denotes a digitally controlled crystal oscillator including a first vibrating unit 322, a first oscillation circuit 294, and a variable reactance circuit 295. Reference numeral 325 denotes a temperature sensor including a second vibrating unit 323 and a second oscillation circuit 299. . Here, the crystal resonator 321 is so arranged that the second vibrating section 323 has a resonance frequency-temperature characteristic that enables easy temperature detection, and the first vibrating section 322 has a stable resonance frequency-temperature characteristic. The three crystal blanks that are configured are set directly at the cutout angle, thickness, and crystal axis relationship, and are directly joined.

In the digital temperature compensated crystal oscillator configured as described above, the storage device stores data in which the digital signal obtained by converting the output signal of the temperature sensor by the A / D converter and the control signal of the variable reactance circuit correspond to each other. It is stored in advance. Thereby, the reactance of the variable reactance circuit changes in response to the temperature change, and the output frequency of the digitally controlled crystal oscillator can be stabilized. In addition, since the vibrating part for the temperature sensor and the vibrating part for the digitally controlled crystal oscillator are integrally formed, there is almost no temperature difference between them, and the temperature information of the vibrating part for the digitally controlled oscillator can be obtained accurately. it can.

As described above, according to each of the twentieth to twenty-third embodiments of the present invention, any one of the ninth, tenth, and twelfth embodiments of the present invention can be arbitrarily set at any resonance frequency. By using a crystal oscillator that can extract two vibrations with temperature characteristics, the vibrating parts for the temperature sensor and the digitally controlled crystal oscillator can be integrally formed, and each vibrating part has the optimal temperature characteristics according to the purpose. Therefore, a digital temperature-compensated crystal oscillator that is small, inexpensive, and can perform high-precision temperature compensation even with a small number of bits can be realized.

In the twenty-second embodiment, the vibrator 311 of the first vibrating part 312 is the same as that of the tenth embodiment (FIG. 1).
A crystal blank 197 is formed by bonding three crystal blanks (191, 192, 193) shown in 3), and has higher resonance frequency-temperature characteristics and higher stability than the twentieth and twenty-first embodiments. It is possible to obtain a digital temperature-compensated crystal oscillator with higher precision and lower bits.

In the twenty-third embodiment, the two first
Since a region smaller than the thickness of either of the two vibrating parts is provided between the second vibrating parts 322 and 323, the isolation between the elastic vibrations generated in each of the two vibrating parts can be increased. In the twenty-third embodiment of the present invention, the thickness between the two first and second vibrating parts is configured to be smaller than the thickness of either of the two vibrating parts. However, it is not always necessary to reduce the thickness. The fourteenth embodiment of the present invention (FIG. 1)
7) The two vibrating portions 23 like the quartz oscillator described in
The same effect can be obtained even when the thickness of the direct joining portion 236 between the vibrating portions 4 and 235 is made larger than the thickness of both vibrating portions 234 and 235.

(Twenty-fourth Embodiment) FIG. 27 is a block diagram showing a configuration of a digital temperature-compensated crystal oscillator according to a twenty-fourth embodiment of the present invention (invention 11). In FIG. 27, reference numeral 331 denotes the first embodiment of the present invention.
This is a crystal resonator that can take out three vibrations having arbitrary resonance frequency and temperature characteristics by itself as shown in the first embodiment (FIG. 14). 332, 333 and 334 are three first, second and third vibrating parts formed on the quartz oscillator 331. Reference numeral 335 denotes a digitally controlled crystal oscillator including a first vibrating unit 332, a first oscillation circuit 294, and a variable reactance circuit 295. Reference numeral 336 denotes a first temperature including a second vibrating unit 333 and a second oscillation circuit 299. A sensor 337 is a second temperature sensor including a third vibrating unit 334 and a third oscillation circuit 338. here,
The second and third vibrating parts 333 and 334 have a resonance frequency-temperature characteristic that enables easy temperature detection,
The two crystal pieces constituting the crystal resonator 331 are set to have a cut-out angle, a thickness, and a crystal axis relationship, and are directly joined so that the vibrating portion 332 has stable resonance frequency-temperature characteristics.

As described above, according to the twenty-fourth embodiment of the present invention, in addition to the effects of the twentieth to twenty-third embodiments of the present invention, the first and second temperature sensors 336 and 337 are provided.
Since temperature detection is performed using both of them, temperature detection can be performed more accurately.

In the twenty-fourth embodiment of the present invention,
Four or more sets of excitation electrodes may be provided, and the same effect is obtained even when four or more sets of excitation electrodes are formed.

In each of the twentieth to twenty-fourth embodiments of the present invention, there is no limitation on the cutout angle, thickness, shape, and number of crystal blanks, and the vibrating section is freely set so as to have desired characteristics. be able to. Further, the relationship between the crystal axes at the time of bonding can be freely set so that desired characteristics can be obtained. Further, a frequency counter or the like can be used as the A / D converter. Further, as the variable reactance circuit, for example, a method of applying the output voltage of the D / A converter to the variable capacitance diode using a D / A converter and a variable capacitance diode, or directly changing the capacitance value by switching using a digital signal. It is possible to use a method of changing.

(Twenty-fifth and twenty-sixth embodiments) Hereinafter, twenty-fifth and twenty-sixth embodiments of the present invention will be described.
2) will be described with reference to the drawings.

FIGS. 28 (a) and 28 (b) show the structure of a quartz filter according to a twenty-fifth embodiment. FIG. 28 (a) is a plan view and FIG. 28 (b) is a side view. In FIG. 28, reference numerals 341 and 342 denote crystal blanks, and reference numerals 344, 345, 346, and 347 denote electrodes. The crystal blanks 341 and 342 have a desired cut-out angle and a desired thickness so that the frequency-temperature characteristics cancel each other, and are directly bonded so that respective crystal axes intersect at a desired angle.
43. The electrodes 344 and 345 and the electrodes 346 and 347 are opposed to each other via a bonded quartz piece 343.

The operation of the thus configured quartz filter will be described below.

Electrodes 344 and 345 and 346 and 347
One of the electrodes is usually grounded. For example, when the electrodes 345 and 347 are grounded, the electrode 344 is used as an input terminal, and the electrode 346 is used as an output terminal, when an electric signal is input to the electrode 344, the bonded crystal blank 343 resonates at a frequency determined by its thickness and elastic constant. . This resonance is transmitted mechanically in the bonded quartz piece 343, and as a result,
An electric field is generated between the electrodes 346 and 347,
Can extract electrical signals from That is, the band-pass filter has a resonance frequency determined by the thickness and elastic constant of the bonded crystal piece 343. Further, the bonded crystal blank 343 is such that the frequency temperature characteristics cancel each other.
1 and 342, the resonance frequency is stable with respect to temperature.

As described above, according to the twenty-fifth embodiment,
Since the electrodes are opposed to each other via two bonded quartz pieces having different frequency-temperature characteristics, which are directly bonded without inclusions, a crystal filter having stable frequency-temperature characteristics can be realized. .

FIGS. 29A and 29B show the structure of a quartz filter according to a twenty-sixth embodiment. FIG. 29A is a plan view and FIG. 29B is a side view. In FIG. 29, 348 is an electrode.
The operation of the twenty-sixth embodiment is similar to that of the twenty-fifth embodiment (FIG. 28).
The structure is similar to that described above, except that the electrode to be grounded is integrated into the electrode 348 to simplify the structure and assembly.

(Twenty-Seventh Embodiment) FIGS. 30A and 30B show the structure of a quartz filter according to a twenty-seventh embodiment of the present invention (the invention according to claim 13).
Is a plan view, and (b) is a side view. In FIG. 30, 3
49 and 350 are crystal blanks, 351, 352 and 35
3 is an electrode. A crystal blank 350 having electrodes 352 and 353 facing each other on both sides and a crystal blank 349 having an electrode 351 formed on one side face the electrode 352 such that the electrodes 351 and 352 face each other via the crystal blank 349. Directly joined at no part.

The operation of the crystal filter configured as described above will be described below. Usually, the electrode 352 is grounded, and the electrodes 351 and 353 are electrodes for inputting and outputting electric signals. For example, when an electric signal is input to the electrode 351, the crystal blank 350 resonates at a frequency determined by its size and elastic constant. Since the crystal blanks 349 and 350 are directly joined, this resonance is mechanically transmitted to the crystal blank 349, an electric field is generated between the electrodes 351 and 352, and an electric signal is output from the electrode 353.

As described above, according to the twenty-seventh embodiment,
By directly joining the two quartz resonators with the electrodes interposed therebetween, resonance can be three-dimensionally coupled, so that a small quartz filter can be realized.

(Twenty-eighth Embodiment) FIGS. 31A and 31B show the structure of a quartz crystal filter according to a twenty-eighth embodiment of the present invention (the invention according to claim 14).
Is a plan view, and (b) is a side view. In FIG. 31, 3
55, 356, 357 and 358 are crystal blanks. Quartz pieces 355 and 356 and 357 and 358 have a desired cutout angle and a desired thickness so that the frequency characteristics cancel each other, and are directly bonded so that the crystal axes intersect at a desired angle. To form bonded crystal pieces 359 and 360.
The operation of this embodiment is the same as that of the twenty-seventh embodiment (FIG. 30), but uses the bonded crystal pieces 359 and 360 instead of the crystal pieces 349 and 350 in FIG. As in the embodiment (FIG. 28), stable frequency-temperature characteristics can be obtained.

In each of the twenty-fifth to twenty-eighth embodiments, the shape of the crystal piece and the electrode is square, but any shape such as a circle may be used. Also, the number of crystal pieces,
There is no limitation on the cutting angle, the thickness, and the crystal axis relation at the time of direct joining. Further, there is no limitation on the number, pattern shape, composition and thickness of the electrodes.

[0148]

As described above, according to the present invention, the excitation electrodes are opposed to each other via a bonded crystal piece in which at least two crystal pieces having different frequency-temperature characteristics are directly bonded without any inclusion. Thus, a crystal resonator having a stable resonance frequency in a wide temperature range can be realized.

[0149]

[0150]

Further, a quartz resonator having a configuration in which excitation electrodes are opposed to each other via a bonded quartz piece in which at least two quartz pieces having different frequency-temperature characteristics are directly bonded without any inclusion is used as a resonance element. Accordingly, a crystal oscillator having a stable output frequency over a wide temperature range and a small, low-current-consumption, high-precision, low-cost analog or digital temperature-compensated crystal oscillator can be realized.

[0152]

Further, by forming at least two sets of opposing electrodes through a bonded quartz piece in which at least two quartz pieces having different frequency-temperature characteristics are directly bonded without any inclusion, the frequency- A crystal filter with stable temperature characteristics can be realized.

In addition, at least two or more quartz pieces and one more electrode than the number of the quartz pieces are alternately overlapped,
In addition, a small crystal filter can be realized by adopting a configuration in which the respective quartz pieces facing each other via the respective electrodes are directly joined at a portion where no electrode is interposed.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a first example of a direct bonding method of a crystal piece used in the present invention.

FIG. 2 is a flowchart showing a second example of the direct bonding method of the crystal blank used in the present invention.

FIG. 3 is a flowchart showing a third example of the direct bonding method of the crystal blank used in the present invention.

FIGS. 4A and 4B are a side view (a) and a plan view (b) of the crystal unit according to the first embodiment of the present invention, and a diagram (c) showing an example of a resonance frequency-temperature characteristic of a bonded crystal blank.

5A and 5B are a side view and a plan view of a crystal unit according to a second embodiment of the present invention.

FIG. 6 is a side view (a) and a plan view (b) of a quartz oscillator according to a third embodiment of the present invention.

FIG. 7 is a side view (a) and a plan view (b) of a crystal unit according to a fourth embodiment of the present invention.

FIG. 8 is a side view (a) and a plan view (b) of a quartz oscillator according to a fifth embodiment of the present invention.

FIG. 9 is a side view (a) and a plan view (b) of a crystal unit according to a sixth embodiment of the present invention.

FIG. 10 is a side view (a) and a plan view (b) of a crystal unit according to a seventh embodiment of the present invention.

FIG. 11 is a side view (a) and a plan view (b) of a crystal resonator according to an eighth embodiment of the present invention.

FIG. 12 is a side view showing a structure of a crystal resonator according to a ninth embodiment of the present invention.

FIG. 13 is a side view showing a structure of a crystal resonator according to a tenth embodiment of the present invention.

FIG. 14 is a side view showing a structure of a crystal unit according to an eleventh embodiment of the present invention.

FIG. 15 is a side view showing a structure of a crystal resonator according to a twelfth embodiment of the present invention.

FIG. 16 is a side view showing a structure of a crystal resonator according to a thirteenth embodiment of the present invention.

FIG. 17 is a side view showing a structure of a crystal resonator according to a fourteenth embodiment of the present invention.

FIG. 18 is a circuit diagram of a crystal oscillator according to a fifteenth embodiment of the present invention.

FIG. 19 is a circuit diagram of an analog temperature compensated crystal oscillator according to a sixteenth embodiment of the present invention.

FIG. 20 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to a seventeenth embodiment of the present invention.

FIG. 21 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to an eighteenth embodiment of the present invention.

FIG. 22 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to a nineteenth embodiment of the present invention.

FIG. 23 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to a twentieth embodiment of the present invention.

FIG. 24 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to a twenty-first embodiment of the present invention.

FIG. 25 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to a twenty-second embodiment of the present invention.

FIG. 26 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to a twenty-third embodiment of the present invention.

FIG. 27 is a block diagram showing a configuration of a digital temperature compensated crystal oscillator according to a twenty-fourth embodiment of the present invention.

FIGS. 28A and 28B are a plan view and a side view showing a structure of a crystal filter according to a twenty-fifth embodiment of the present invention.

FIGS. 29A and 29B are a plan view and a side view showing a structure of a crystal filter according to a twenty-sixth embodiment of the present invention.

FIGS. 30A and 30B are a plan view and a side view showing a structure of a crystal filter according to a twenty-seventh embodiment of the present invention.

FIGS. 31A and 31B are a plan view and a side view showing a structure of a crystal filter according to a twenty-eighth embodiment of the present invention.

FIG. 32 is a side view of a relevant part showing each example of the configuration of a conventional crystal unit.

FIG. 33 is a diagram showing a resonance frequency-temperature characteristic of a conventional AT-cut crystal blank.

FIG. 34 is a diagram showing a typical configuration of a conventional analog temperature compensated crystal oscillator.

FIG. 35 is a diagram showing a typical configuration of a conventional digital temperature compensated crystal oscillator.

36A is a perspective view showing the structure of a conventional quartz filter, and FIG. 36B is a sectional view taken along line aa ′ of FIG.

[Explanation of symbols]

101, 102, 111, 112, 113, 121, 1
22, 131, 132, 141, 142, 151, 15
2,153,161,162,163,171,17
2,181,182,191,192,193,20
1,202, 211, 212, 213, 221, 22
2,223,224,231,232,233,34
1,342,349,350,355,356,35
7, 358, 401, 403, 431 ... crystal blank, 10
3,114,123,133,143,154,16
4,173,184,185,195,196,20
4,205,206,216,217,227,22
8, 237, 238, 402, 404 ... excitation electrode, 1
04, 115, 124, 137, 147, 158, 16
8,174,186,197,207,218,22
9,239,343,359,360 ... bonded crystal pieces, 134,135,144,145,155,15
6,165,166,175,176...
6,146,157,167,177,292,29
3,302,303,312,313,322,32
3, 332, 333, 334: vibrating section, 183, 19
4,203,214,215,225,226,23
4, 235, 236: direct bonding portion, 241, 251,
261,271,281,291,301,311,3
21,331,413,426 ... crystal oscillator, 24
2,253,262,294,299,338,41
1,425: oscillation circuit, 243, 254, 412: output terminal, 252, 414: temperature compensation circuit, 263
295, 424: temperature compensation circuit, 263, 295, 4
24 ... variable reactance circuit, 264,275,28
5,297,423 ... storage device, 265,274,2
98,422 ... A / D converter, 266,273,30
0,305,315,325,336,337,421
... temperature sensors, 267, 296, 304, 314, 3
24,335,427 ... Digital controlled crystal oscillator, 2
72,282,283 ... crystal oscillator, 276,286
... programmable frequency divider, 284 ... frequency counter,
344, 345, 346, 347, 348, 351,
352, 353, 432, 433, 434 ... electrodes, X
... X axis of quartz crystal, Y ... Y axis of quartz crystal, Z ... Z axis of quartz crystal, P ...
... The angle between each crystal axis.

──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 4-31669 (32) Priority date February 19, 1992 (199.2.2.19) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 4-44772 (32) Priority date March 2, 1992 (1992.3.2) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 4-113526 (32) Priority date May 6, 1992 (1992.5.6) (33) Priority claiming country Japan (JP) (72) Inventor Toshio Ishizaki 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Address Matsushita Electric Industrial Co., Ltd. (56) References JP-A-49-3667 (JP, A) JP-A-50-147295 (JP, A) JP-A-63-285195 (JP, A) Japanese Patent Publication Sho 62 -27040 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H03H 3/00 H03B 5/32 H03H 9/19 H03H 9/205 H01L 21/02

Claims (4)

(57) [Claims] 1. A desired cutting angle and a desired thickness.
Having at least two bonding surfaces of the quartz pieces,
Mirror polished and thoroughly washed with cleaning solution to completely remove contaminants
After removal, heat and dry to form a hydrogen bond
By removing the water molecules that remain, only smooth and flat
After terminating with hydroxyl group, contact without inclusions
The bonding force acting between the hydroxyl groups on the bonding surface.
Within the temperature range where the crystal does not undergo phase transition.
It is characterized by heat treatment and direct bonding with stronger bonding force.
Direct joining method of quartz pieces. 2. At least two different frequency-temperature characteristics.
2. A single crystal blank laminated in the thickness direction without inclusions.
A quartz piece joined by the direct joining method of the described quartz piece,
An excitation electrode opposed to the thickness direction of the bonded quartz piece;
When an electric field is applied to the excitation electrode,
A crystal resonator characterized in that a crystal piece vibrates. 3. A quartz resonator according to claim 2, wherein said quartz resonator is a resonance element.
A crystal oscillator characterized by being used as a crystal oscillator. 4. The method for directly joining quartz pieces according to claim 1.
At least two pairs of opposing electrodes on the more bonded quartz pieces
In opposite directions, and one of the pair of counter electrodes
When an electrical signal is input from the
It outputs an electric signal of a specific frequency component.
Crystal filter.