JP2000036724A - Crystal vibrator and its housing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal vibrator and its housing structure which can generate a stable resonance frequency with its small fluctuations, can reduce temporal variation in the generated resonance frequency and improve its frequency precision, and furthermore has advantages such as size reduction, low working cost, and easy designing. SOLUTION: Electrode parts 2 and 3 for excitation are formed on both the surfaces of a crystal substrate 1, and the region sandwiched between the electrode parts 2 and 3 is regarded as an excitation part 4, and axis inversion parts 21, 22 having electric axis (-X) in the opposite directions from the electric axis (X) of the excitation part 4 are formed on both the sides of the excitation part 4 in the crystal substrate 1, and connection terminal parts 25 and 26 which are connected electrically to the electrode parts 2 and 3 are formed outside the axis inversion parts 21 and 22 of the crystal substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitably used for a clock generator of an information device such as a computer, a local oscillator and a filter of a wireless communication device, and has a stable resonance frequency and a filter even when the ambient temperature fluctuates. The present invention relates to a crystal resonator and a housing structure thereof capable of obtaining a frequency and further reducing the generated aging of a resonance frequency significantly, thereby improving the frequency accuracy.

[0002]

2. Description of the Related Art Conventionally, as a vibrator used in a resonance circuit of an oscillator for generating an electric signal of a constant frequency, a crystal vibrator capable of obtaining a stable resonance frequency with respect to a temperature change is known. FIG. 6 is a perspective view showing a conventional crystal unit. In the figure, reference numeral 1 denotes an electric axis (X) and 2
AT-cut quartz substrate having a temperature coefficient of frequency of 0 at 5 ° C. is 0, 2, and 3 are excitation electrodes made of aluminum, gold, etc. formed on both surfaces of quartz substrate 1, and 4 are electrodes 2, 3
The excitation section is a box-shaped area sandwiched between the sections. In this crystal resonator, by applying a high-frequency voltage near the resonance frequency between the electrodes 2 and 3, electric vibration having a specific frequency in the range of about 1 kHz to 100 MHz can be generated.

The above-described resonance frequency of the crystal unit has a characteristic represented by a cubic curve when the ambient temperature is used as a parameter. Therefore, when the temperature fluctuation is small, the fluctuation of the resonance frequency does not matter. However, when used in an environment where the temperature fluctuates greatly, the fluctuation of the resonance frequency becomes large and cannot be ignored. Therefore, by combining with a temperature-sensing element that can obtain a temperature compensation voltage that cancels out this characteristic, for example, a temperature compensation circuit using a thermistor whose temperature characteristic is represented by an exponential function, the resonance frequency can be reduced to the ambient temperature. Is provided with a temperature-compensated crystal oscillator (TCXO) that is changed substantially linearly.

In general, if twins are present in a crystal for an electronic device, the characteristics of the device are adversely affected. Therefore, it is important that twins are not formed in the crystal. In a crystal oscillator and a crystal oscillator, it is natural that there is no twin in the crystal substrate used as the oscillator.

However, the above-described crystal oscillator (TC
XO) requires several electronic components in addition to the thermistor in order to form a temperature compensation circuit, and the number of electronic components used increases, resulting in a higher price.
There are various disadvantages, such as complicated adjustment of the circuit of the crystal oscillator. On the other hand, the resonance frequency-temperature characteristic of the quartz substrate represented by the cubic curve is considered to be a characteristic unique to the quartz substrate, and it has been considered that there is no room for improvement in the quartz substrate itself.

[0006] In general, quartz has an α · at 573 ° C (Tc).
β transition occurs, but the transition temperature decreases due to stress, etc.
It is known that the electric axis (X axis) is inverted at a temperature lower than Tc. Accordingly, the present inventors have conducted intensive studies and found that by applying a heat treatment by attaching a metal electrode to the surface of a quartz substrate, a quartz crystal may be formed at a temperature much lower than Tc depending on the cutting direction of the substrate and the type of metal. By inverting the electric axis of the substrate and forming an axis inversion portion having an electric axis in the opposite direction to the electric axis of the excitation portion in the quartz substrate, stable resonance even when the ambient temperature fluctuates. They found that a frequency could be obtained, and proposed a crystal resonator and a method for manufacturing the same (Japanese Patent Application No. 9-10899).
No. 4).

FIG. 7 is a perspective view showing a crystal unit proposed by the present inventors, and FIG. 8 is a sectional view taken along the line II of FIG. In the figure, reference numerals 11 and 12 denote axis reversing parts formed in the quartz substrate 1 and near both sides of the excitation unit 4 and having an electric axis (−X) in the opposite direction to the electric axis (X) of the excitation unit 4. is there. 7 and 8, W represents the electrodes 2 and 3.
, L is the length of the electrodes 2 and 3, d is the distance between the excitation section 4 and the axis reversing sections 11 and 12, s is the length of the axis reversing sections 11 and 12,
t is the thickness of the quartz substrate 1, and f is the amplitude distribution of the vibration displacement in the length direction.

In this crystal resonator, when a high-frequency voltage near the resonance frequency is applied between the electrodes 2 and 3, an amplitude distribution f of vibration displacement as shown in FIG. 8 is obtained. That is, due to the energy trapping effect based on the mass addition effect of the electrodes 2 and 3, most of the vibration energy concentrates on the excitation unit 4, but a part leaks to reach the axis reversing units 11 and 12, and as a result, the temperature characteristics Is improved.

Here, the temperature characteristics of the crystal unit will be described with reference to FIG. In FIG. 9, A is the optimal characteristic of the crystal unit having the axis reversal part, and B is the AT without the axis reversal part.
The characteristics of the cut quartz resonator, C is the X of the AT cut quartz substrate
Characteristic D of the crystal resonator whose axis is inverted is a result of an experiment performed to confirm the principle of temperature compensation of the crystal resonator having the axis inversion portion. The sample used in the above experiment (D) had t of 205 μm, W of 5.0 mm, and L of 2.5 m.
m and s were 2.5 mm and d was 2.0 mm, and the heat treatment condition was 550 ° C. for 1 hour and 30 minutes. The frequency fr used for the measurement was 8.0 MHz.

As is clear from the above, the resonance frequency of the AT-cut crystal resonator (B) is represented by a cubic curve, and has a negative temperature coefficient near room temperature. On the other hand, the inverted crystal unit (C) has an extremely large positive temperature coefficient.
Therefore, as shown in FIG. 7, by leaking a part of the vibration energy (the bottom part of the amplitude distribution f) to the axis inverting parts 11 and 12, the positive temperature coefficient and the negative temperature coefficient are canceled out, The optimum characteristic (A) is obtained. That is, its temperature coefficient becomes almost 0 in a temperature range of about 0 to 70 ° C.,
When the temperature exceeds 70 ° C., the temperature slightly increases as the temperature rises.

As described above, a part of the vibration energy is leaked to the axis reversing parts 11 and 12 to cancel the positive temperature coefficient and the negative temperature coefficient, thereby compensating the temperature characteristics. Thus, even when the ambient temperature fluctuates, a stable resonance frequency can be obtained without using a temperature compensation circuit or the like.

[0012]

Incidentally, the above-described quartz resonator may be mounted on a substrate as it is, and may be mounted on a housing for various reasons such as protection of itself and easiness of handling. It may take a structure. As the housing structure, the crystal unit is fitted into the support member provided on the metal frame, and the electrodes for excitation of the crystal unit and the lead wires for external connection are electrically connected using a wire or conductive adhesive. After connection, these are generally covered with a metal cover or the like.

However, in the case of this crystal unit, which is particularly remarkable in the case of a housing structure, the material and the stress of the member for supporting the crystal unit and the conductive adhesive greatly affect the crystal unit. The resonance frequency fluctuates, and there is a problem that a stable resonance frequency cannot be generated. Further, since the support member and the conductive adhesive easily change over time, the magnitude of the stress also changes over time. As a result, there is a problem that the secular change of the resonance frequency generated from the crystal unit cannot be ignored, and the frequency accuracy is reduced. Further, when a circuit is designed using this crystal resonator, there is a problem that the design becomes complicated because it is necessary to consider the stress received from the support member and the conductive adhesive.

The present invention has been made in view of the above circumstances, and has a small fluctuation of a generated resonance frequency, can generate a stable resonance frequency, and can prevent a change of the generated resonance frequency with time. Extremely small, its frequency accuracy can be improved, and further downsizing is possible,
It is an object of the present invention to provide a crystal unit having advantages such as low processing cost and easy design, and a housing structure thereof.

[0015]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides the following quartz resonator and its housing structure. That is, in the crystal unit according to the first aspect, excitation electrode portions are respectively formed on both surfaces of the crystal substrate, and a region sandwiched between the electrode portions is used as an excitation portion, and both sides of the excitation portion in the crystal substrate are provided. On the other hand, an axis reversal part having an electric axis in a direction opposite to the electric axis of the excitation part is formed, and a connection terminal part conducting to the electrode part is formed at each position outside the axis reversal part of the quartz substrate. It is characterized by doing.

According to a second aspect of the present invention, there is provided a crystal resonator according to the first aspect, wherein the connection terminal portions are formed on both end faces of the quartz substrate or on main surfaces near the both end faces. It is characterized by:

According to a third aspect of the present invention, in the quartz resonator according to the first or second aspect, the axis inversion portion is formed along the z′-axis direction of the quartz substrate.

According to a fourth aspect of the present invention, there is provided the crystal resonator according to the first or second aspect, wherein the crystal reversing unit is provided outside the excitation unit in the crystal substrate and separated from the axis reversing unit. A second axis reversing part extending in a direction perpendicular to the extending direction is formed.

According to a fifth aspect of the present invention, in the crystal unit according to the fourth aspect, the axis inversion portion is formed along an x-axis direction of the crystal substrate, and the second axis inversion portion is formed in the crystal substrate. ,
The quartz substrate is formed along the z'-axis direction.

According to a sixth aspect of the present invention, there is provided a housing for a crystal unit according to any one of the first to fifth aspects, and a pair of the crystal unit according to any one of the first to fifth aspects, which supports the crystal unit and is electrically connected to the outside. And a housing provided so as to cover the crystal unit and the pair of support units and fixing the support unit. Each connection terminal of the crystal unit is electrically connected to the support unit. It is characterized by being connected to.

In the quartz resonator according to the first, second, or third aspect of the present invention, an axis reversing portion having an electric axis in a direction opposite to an electric axis of the exciting portion is formed on both sides of the exciting portion in the quartz substrate. In addition, since the connection terminal portion that is electrically connected to the electrode portion is formed at each position outside the axis inversion portion of the crystal substrate, the connection terminal portion is generated at the time of connection or thereafter due to the confinement effect of the axis inversion portion. It is possible to remarkably reduce the influence of a change in mass or stress on the electrode part for excitation. Thus, the fluctuation of the generated resonance frequency is reduced, and a stable resonance frequency can be generated.

Further, since the influence on the excitation electrode portion is significantly reduced, the secular change of the resonance frequency is significantly reduced, the frequency accuracy is improved, and the connection terminal portion is located close to the excitation electrode portion. Since it can be provided, the size of the crystal unit can be reduced, and the processing cost can be reduced. Further, when designing the substrate of the crystal resonator, it is possible to perform the design ignoring the above-mentioned influence on the electrode portion for excitation, which greatly facilitates the design and improves the efficiency of the design work.

According to a fourth aspect of the present invention,
By forming a second axis-reversing part that is separated from the axis-reversing part and extends in a direction perpendicular to the direction in which the axis-reversing part extends outside the excitation part in the quartz substrate, When the second axis reversing part is used for temperature compensation, the temperature characteristics of the crystal resonator are improved. Thus, for example, a temperature compensating circuit using a thermistor or the like becomes unnecessary, and the circuit configuration can be reduced in size.

According to a sixth aspect of the present invention, there is provided a housing for a crystal unit according to any one of the first to fifth aspects, and a pair of the crystal unit which supports the crystal unit and is electrically connected to the outside. And a housing provided so as to cover the crystal unit and the pair of support units and fixing the support unit. Each connection terminal of the crystal unit is electrically connected to the support unit. Due to the confinement effect of the axis reversing part, the influence of the mass and stress of the support part and the member connecting the support part and the connection terminal part on the electrode part for excitation can be significantly reduced. Will be possible. As a result, when designing the substrate of the crystal resonator, it is possible to perform the design ignoring the above-described effects, and as a result, the design becomes very easy and the efficiency of the design work is improved.

Further, the influence of mass and stress on the excitation electrode portion of the support portion and the member connecting the support portion and the connection terminal portion due to aging after mounting is extremely small. The change is extremely small, and the frequency accuracy is improved. In addition, since the support portion and the member connecting the support portion and the connection terminal portion can be brought close to the excitation electrode portion, the size can be reduced.

[0026]

Embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a plan view showing a crystal unit according to a first embodiment of the present invention.
Is an electric axis of the excitation unit 4 formed along the x-axis direction of the crystal substrate 1 in the AT-cut crystal substrate 1 and near both sides in the z′-axis direction which is near the short side of the excitation unit 4. Axis reversing parts having an electric axis (−X) in the opposite direction to (X), 23, 24
In the quartz substrate 1, in the vicinity of both sides in the x-axis direction near the long side of the excitation unit 4, the direction in which the axis inversion units 21 and 22 extend (the x-axis direction) A second axis reversing part for temperature compensation extending in a direction (z ′ axis direction) orthogonal to the direction (z ′ axis direction).

Reference numeral 25 denotes a connection terminal portion formed along the x-axis direction of the crystal substrate 1 at a position outside the axis reversing portion 21 of the crystal substrate 1 and is electrically connected to the electrode portion 2. Reference numeral 26 denotes an axis of the crystal substrate 1. A connection terminal portion formed at a position outside the inversion portion 22 along the x-axis direction of the quartz substrate 1 and electrically connected to the electrode portion 3.

In this crystal resonator, the connection terminals 25, 2
6 is connected to the terminal of an external high-frequency power supply (not shown), and a high-frequency voltage near the resonance frequency is applied between the electrodes 2 and 3 through these connection terminals 25 and 26, the energy based on the mass addition effect of the electrodes 2 and 3 Due to the confinement effect, most of the vibration energy concentrates on the excitation unit 4 and oscillates at a resonance frequency. Part of the vibration energy leaks and reaches the axis reversing parts 23 and 24, and as a result, the temperature characteristics are improved.

As described above, a part of the vibration energy is leaked to the axis reversing parts 23 and 24 to cancel the positive temperature coefficient and the negative temperature coefficient, thereby compensating the temperature characteristics. As a result, even when the ambient temperature fluctuates, a stable resonance frequency can be obtained without using a temperature compensation circuit or the like.

FIG. 2 is a diagram showing an electric circuit used for measuring the resonance characteristics of the crystal unit according to the present embodiment. The crystal unit used here has one X An axis reversal area (axis reversal part) 27 is formed, and the X axis reversal area 27 is formed.
One excitation part 4a is formed on one side, and two excitation parts 4b and 4c are formed on the other side in parallel with each other.

Here, the width of the X-axis inversion area 27 is set to 1.5.
mm and the length were 4.5 mm. Further, the excitation units 4a to 4a
The electrode c was formed of a Cr thin film, and the width of these electrodes was 2.5 mm, the length was 3 mm, the interval was 4.5 mm, and the film thickness was 2000 mm. Exciting parts 4a to 4 of this crystal unit
By connecting c to the network analyzer 28, resonance characteristics can be measured.

FIGS. 3A to 3C are diagrams showing the measurement results of the resonance characteristics of the crystal unit according to the present embodiment.
(A), the excitation units 4a and 4c are in an open state, and the excitation unit 4b
FIG. 3 (b) shows the resonance characteristics when the exciters 4a and 4b are in the short state and the exciters 4c are in the open state, and FIG. 3 (c) shows the resonance characteristics when the exciters 4c and 4b are in the open state.
The resonance characteristics when a is in the open state and the excitation units 4b and 4c are in the short state are shown.

3 (a) and 3 (b), the waveform and the frequency of the maximum peak (f ₀ = 5.5100 MHz) are the same, and it can be seen that there is no influence of twinning. Further, in FIG. 3C, the frequency of the maximum peak is clearly separated into two (f ₁ = 5.5084 MHz, f ₂ = 5.5122).
MHz two), which indicates that the twins have excellent separation ability.

As described above, according to the crystal resonator of the present embodiment, the quartz oscillator 1 is provided along the x-axis direction of the crystal substrate 1 in the vicinity of both sides of the excitation unit 4 in the z′-axis direction. An axis reversing unit 21 having an electric axis in a direction opposite to the electric axis of the excitation unit 4,
22 are formed in the quartz substrate 1 in the vicinity of both sides of the excitation section 4 in the x-axis direction, separated from the axis reversing sections 21 and 22 and directions in which the axis reversing sections 21 and 22 extend (x-axis direction). Axis inverting portions 23 and 24 for temperature compensation extending in a direction (z ′ axis direction) orthogonal to the axis of the crystal substrate 1 in the x-axis direction at a position outside the axis inverting portion 21 of the crystal substrate 1. Along the electrode part 2
Is formed, and a connection terminal portion 26 is formed at a position outside the axis reversing portion 22 of the crystal substrate 1 so as to conduct to the electrode portion 3 along the x-axis direction of the crystal substrate 1. Due to the confinement effect of the axis reversing portions 21 and 22, the influence of the change in the mass or the stress generated in the connection terminal portions 25 and 26 during and after connection on the excitation electrode portions 2 and 3 can be significantly reduced. Therefore, the fluctuation of the generated resonance frequency can be reduced, and a stable resonance frequency can be generated.

Further, it is possible to set the best aspect ratio in consideration of spurious without being affected by the shape of the quartz substrate 1. As a result, the processing accuracy of the quartz substrate 1 is improved, and Processing costs can be greatly reduced. Further, since the formation of the axis reversing portions 21 and 22 is reduced to １ ／, the size of the crystal substrate 1 can be reduced.

When this crystal unit is fixed to a support member of a housing or the like, the confinement effect of the axis reversing units 21 and 22 causes the connection terminal unit 2 to the excitation electrode units 2 and 3.
Since the influence of the mass and the stress of the elements 5 and 26 can be remarkably reduced, these effects can be neglected in the substrate design of the crystal unit, and the design becomes extremely easy.

When this crystal resonator is mounted on a substrate, the influence of the mass and stress of the connection terminals 25 and 26 due to aging after mounting on the excitation electrodes 2 and 3 is significantly reduced. Therefore, the secular change of the frequency can be remarkably reduced, and the accuracy of the resonance frequency of the crystal resonator can be improved. Also, the connection terminal 25,
26 can be provided close to the excitation electrode portions 2 and 3, so that the size of the crystal resonator can be reduced.

(Second Embodiment) FIG. 4 is a plan view showing a quartz oscillator according to a second embodiment of the present invention. In the drawing, reference numerals 31 and 32 denote an AT-cut quartz substrate 1 and an excitation unit 4. An axis inverting portion formed along the z′-axis direction of the quartz substrate 1 near both sides in the x-axis direction, which is near the long side, and having an electric axis opposite to the electric axis of the excitation section 4; Reference numeral 33 denotes a connection terminal portion formed at a position outside the axis inversion portion 31 of the crystal substrate 1 along the z′-axis direction of the crystal substrate 1 and is electrically connected to the electrode portion 2. Reference numeral 34 denotes a connection terminal portion from the axis inversion portion 32 of the crystal substrate 1. An electrode portion 3 formed at an outer position along the z′-axis direction of the quartz substrate 1
This is a connection terminal portion that conducts to the terminal.

In this crystal resonator, the connection terminals 33, 3
4 is connected to the terminal of an external high-frequency power supply (not shown), and a high-frequency voltage near the resonance frequency is applied between the electrodes 2 and 3 by the connection terminal portions 33 and 34, the energy based on the mass addition effect of the electrodes 2 and 3 Due to the confinement effect, most of the vibration energy concentrates on the excitation unit 4 and oscillates at a resonance frequency. Part of the vibration energy leaks and reaches the axis reversing parts 31 and 32, and as a result, the temperature characteristics are improved.

As described above, a part of the vibration energy is leaked to the axis reversing parts 31 and 32 to cancel the positive temperature coefficient and the negative temperature coefficient, thereby compensating the temperature characteristics. As a result, even when the ambient temperature fluctuates, a stable resonance frequency can be obtained without using a temperature compensation circuit or the like.

As described above, the same effects as those of the quartz resonator according to the first embodiment described above can be obtained in the quartz resonator according to the present embodiment. In addition, since the long axis reversing parts 31 and 32 are formed near both sides in the x-axis direction near the long side of the excitation part 4, the mass change generated in the connection terminal parts 33 and 34 at the time of connection and thereafter. And the influence of the stress on the excitation electrode portions 2 and 3 can be significantly reduced. Therefore, the fluctuation of the generated resonance frequency can be made smaller, and a more stable resonance frequency can be generated.

In the quartz oscillators of the first and second embodiments, the excitation unit 4 and the axis reversing units 21 to 24 (3
The shapes of (1, 32) are parallel to each other as described above,
For example, the excitation unit 4 and the axis reversing units 21 to 24 (31, 32)
The horizontal cross section of each opposing surface is comb-shaped, and the horizontal cross section of each opposing upper end of the excitation section 4 and the axis reversing sections 21 to 24 (31, 32) is comb-shaped and the horizontal section of each lower end is horizontal. Various shapes such as a shape having parallel cross sections are possible.

(Third Embodiment) FIG. 5 is a perspective view showing a housing structure of a quartz oscillator according to a third embodiment of the present invention. In the drawing, a quartz oscillator 41 is an AT-cut quartz substrate 1. Within the vicinity of both sides of the excitation unit 4 in the x-axis direction, and along the z′-axis direction of the quartz substrate 1, axis inversion units 42 and 43 having an electric axis opposite to the electric axis of the excitation unit 4 are formed. Then, a connection terminal portion 44 that is electrically connected to the electrode portion 2 along the z′-axis direction of the crystal substrate 1 is formed at a position outside the axis inversion portion 42 of the crystal substrate 1. An excitation unit 4 is provided at an outer position along the z′-axis direction of the quartz substrate 1.
Is formed with a connection terminal portion that is electrically connected to the other electrode portion (not shown).

The quartz oscillator 41 is fitted into a pair of quartz piece support portions 53 provided on a metal frame (housing) 51 with an insulating glass 52 interposed therebetween.
The connection terminal section 44 is adhered and fixed to the crystal blank supporting section 53 with a conductive adhesive or the like. These crystal blank support parts 5
3, 53 are a pair of lead terminals 54, 54 extending downward.
The crystal resonator 41 and the whole quartz crystal piece supporting portions 53 are covered with a metal cover 55.

According to the housing structure of this embodiment, due to the confinement effect of the axis reversing portions 42, 43, the influence of the mass and stress of the support material of the crystal blank supporting portions 53, the adhesive of the bonding portion and the like is extremely small. Therefore, in the substrate design of the crystal unit, these effects can be ignored and the design can be made extremely easy.

When this crystal resonator is mounted on a substrate, the crystal piece supporting portions 53, 53 due to aging after mounting are provided.
This makes it difficult for the mass and stress of the adhesive and the like of the support member and the bonding portion to be changed, so that the secular change of the frequency can be remarkably reduced, and the accuracy of the resonance frequency of the crystal resonator can be improved. In addition, since the crystal blank supporting portions 53, 53 and the adhesive portion can be provided close to the excitation electrode portion 2, the size of the crystal resonator can be reduced.

[0047]

As described above, according to the first aspect of the present invention,
According to the crystal resonator described in 2 or 3, an axis reversing portion having an electric axis in a direction opposite to an electric axis of the excitation portion is formed on both sides of the excitation portion in the crystal substrate, and the axis of the crystal substrate is formed. Since the connection terminal portion that is electrically connected to the electrode portion is formed at each position outside the inversion portion, a change in mass or stress generated in the connection terminal portion at the time of connection or thereafter due to the confinement effect of the axis inversion portion causes an excitation. The effect on the electrode portion can be significantly reduced. Therefore, the fluctuation of the generated resonance frequency can be reduced, and a stable resonance frequency can be generated.

Further, since the influence on the excitation electrode portion is significantly reduced, the aging of the resonance frequency can be significantly reduced, and the frequency accuracy can be improved. Further, since the connection terminal portion can be provided close to the excitation electrode portion, the size of the crystal resonator can be reduced, and the processing cost can be reduced. Furthermore, when designing the substrate of the crystal unit, it is possible to ignore the above-mentioned effects on the electrodes for excitation, so that the design becomes very easy and the efficiency of the design work can be improved. it can.

According to a fourth aspect of the present invention, a direction away from the axis reversing part and perpendicular to a direction in which the axis reversing part extends is provided outside the excitation part in the crystal substrate. Formed in the second axis reversal part extending to
The temperature characteristics of the crystal resonator can be improved by using the axis reversal part for temperature compensation. Therefore, a conventional temperature compensation circuit is not required, and the circuit configuration can be reduced in size.

According to a sixth aspect of the present invention, there is provided a crystal resonator housing structure according to any one of the first to fifth aspects, wherein the crystal resonator is supported and electrically connected to the outside. A pair of support portions, the quartz oscillator and
A housing provided to cover the pair of support portions and fixing the support portions, wherein each connection terminal portion of the crystal unit is
Since each of the support portions is electrically connected to each other, the effect of the mass and stress of the support portion and the member connecting the support portion and the connection terminal portion on the excitation electrode portion due to the confinement effect of the axis reversing portion. Can be significantly reduced.
Therefore, the above-described influence can be ignored when designing the substrate of the crystal unit, and as a result, the design becomes very easy, and the efficiency of the design work is improved.

Further, the influence of the mass and stress on the excitation electrode portion of the support portion and the member connecting the support portion and the connection terminal portion due to aging after mounting is significantly reduced. Aging can be significantly reduced, and frequency accuracy can be improved. In addition, since the support portion and the member connecting the support portion and the connection terminal portion can be brought close to the excitation electrode portion, the size can be reduced.

As described above, the fluctuation of the generated resonance frequency is small, and a stable resonance frequency can be generated. Further, the generation of the resonance frequency is remarkably small over time, and the frequency accuracy can be improved. ,
It is possible to provide a crystal resonator having advantages such as downsizing, low processing cost, and easy design, and a housing structure thereof.

[Brief description of the drawings]

FIG. 1 is a plan view showing a crystal resonator according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a resonance characteristic measuring circuit of the crystal unit according to the first embodiment of the present invention.

FIGS. 3A and 3B are diagrams showing measurement results of resonance characteristics of the crystal unit according to the first embodiment of the present invention, wherein FIG.
FIG. 3C shows a case where the excitation unit 4c is in an open state and the excitation unit 4b is in a short state, FIG. 3C shows a case where the excitation units 4a and 4b are in a short state, and FIG. FIG. 7 is a diagram showing respective resonance characteristics when the excitation units 4b and 4c are in a short state.

FIG. 4 is a plan view showing a crystal resonator according to a second embodiment of the present invention.

FIG. 5 is a perspective view illustrating a housing structure of a crystal unit according to a third embodiment of the present invention.

FIG. 6 is a perspective view showing a conventional crystal unit.

FIG. 7 is a perspective view showing another conventional crystal unit.

FIG. 8 is a sectional view taken along the line II of FIG. 7;

FIG. 9 is a diagram illustrating a relationship between a resonance frequency and a temperature characteristic of another conventional crystal unit.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 AT-cut quartz substrate 2, 3 Exciting electrode 4, 4a-4c Exciting section 11, 12 Axis reversing section 21, 22 Axis reversing section 23, 24 Axis reversing section for temperature compensation (second axis reversing section) 25, 26 Connection terminal part 31, 32 Axis reversal part 33, 34 Connection terminal part 41 Crystal oscillator 42, 43 Axis reversal part 44 Connection terminal part 51 Metal frame (housing) 52 Insulating glass 53 Quartz piece support part 54 Lead terminal 55 Metal cover W Electrode width L Electrode length d Distance between excitation part and axis reversal part s Length of axis reversal part f Amplitude distribution of vibration displacement in length direction A Optimal characteristics of crystal unit B AT cut Characteristics of the crystal unit C Characteristics of the crystal unit after the inversion processing D Results of the experiment for confirming the principle of temperature compensation X Electric axis -X Electric axis in the opposite direction

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Terumo Ito 1-297 Kitabukuro-cho, Omiya-shi, Saitama F-term in Mitsubishi Materials Corporation General Research Laboratory 5J033 AA04 BB03 CC02 CC04 CC13 DD02 EE02 EE03 EE11 FF11 FF14 GG06 GG15

Claims (6)

[Claims] An electrode portion for excitation is formed on both surfaces of a quartz substrate, and a region sandwiched between the electrode portions is used as an excitation portion, and the excitation portion of the excitation portion is provided on both sides of the excitation portion in the quartz substrate. Forming an axis inversion portion having an electric axis in a direction opposite to the electric axis, and forming a connection terminal portion that is electrically connected to the electrode portion at each position outside the axis inversion portion of the quartz substrate. Crystal oscillator. 2. The crystal unit according to claim 1, wherein said connection terminal portion is formed on one of both end surfaces of said quartz substrate or on a main surface near said both end surfaces. 3. The apparatus according to claim 1, wherein the axis reversing portion is formed along a z′-axis direction of the quartz substrate.
Or the crystal resonator according to 2. 4. Outside the excitation section in the quartz substrate,
3. The crystal resonator according to claim 1, further comprising a second axis-reversing part that is separated from the axis-reversing part and extends in a direction orthogonal to a direction in which the axis-reversing part extends. Child. 5. The method according to claim 1, wherein the axis inversion portion is formed along an x-axis direction of the quartz substrate, and the second axis inversion portion is formed along a z ′ axis direction of the quartz substrate. The quartz oscillator according to claim 4, wherein 6. A quartz oscillator according to claim 1, a pair of supporting portions for supporting said quartz oscillator and electrically connecting to the outside, and said quartz oscillator and said one. A housing provided to cover the pair of support portions and fixing the support portions, wherein each connection terminal of the crystal unit is electrically connected to each of the support portions. Vibrator housing structure.