JP2003273682A - Frequency control method for piezoelectric vibrator, piezoelectric vibrator, and piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frequency control method for a piezoelectric vibrator by which frequency and temperature characteristics are simultaneously controlled. <P>SOLUTION: When the main vibration frequency of the piezoelectric vibrator is higher than a target value (S74) and a primary temperature coefficient in the frequency and temperature characteristics is higher than a target value (S76), a fine control film is added to a central portion on the surface of an exciting electrode (S80) and when the primary temperature coefficient is lower than the target value (S76), the fine control film is added to a peripheral edge on the surface of the exciting electrode (S82). When the main vibration frequency is lower than the target value (S74) and the primary temperature coefficient is lower than the target value (S84), on the other hand, an electrode material is removed from the central portion on the surface of the exciting electrode (S86) and when the primary temperature coefficient is higher than the target value (S84), the electrode material is removed from the peripheral edge on the surface of the exciting electrode (S88). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrating reed frequency adjusting method utilizing a thickness shear vibration, a piezoelectric vibrating reed and a piezoelectric device.

[0002]

2. Description of the Related Art In order to obtain a constant frequency in an electric circuit, a piezoelectric device mounted with a piezoelectric vibrating reed is widely used. The piezoelectric vibrating piece is obtained by dividing a piezoelectric substrate cut out from a piezoelectric material such as quartz at a predetermined angle into small flat plates and forming excitation electrodes on both sides.

In particular, the piezoelectric vibrating reed utilizing the thickness shear vibration is widely used because of its excellent frequency stability, but it is necessary to match the main vibration frequency with the target frequency with high accuracy. The main vibration frequency largely depends on the thickness of the piezoelectric material, but the crystal cut angle and the thickness of the excitation electrode, which affect the main vibration frequency, inevitably vary, so variations in the finished frequency of the piezoelectric vibrating piece are also avoided. Absent. Therefore, the frequency is finely adjusted after the piezoelectric vibrating piece is formed. The fine adjustment of the frequency is performed by adding a fine adjustment film to the surface of the excitation electrode or removing the excitation electrode. When the finished frequency of the piezoelectric vibrating piece is higher than the target frequency, the main vibration frequency is made to match the target value by forming a fine adjustment film on the entire surface of the excitation electrode. On the other hand, when the finish frequency of the piezoelectric vibrating piece is lower than the target frequency, the main vibration frequency is made to match the target value by slightly removing the electrode material from the entire surface of the excitation electrode.

[0004]

While there is a demand for a piezoelectric vibrating reed having a small variation in the main vibration frequency due to a temperature change, the frequency-temperature characteristic of the thickness-sliding piezoelectric vibrating reed is shown in FIG.
It becomes a cubic curve as shown in, and can be generally expressed by the following equation.

[Equation 1] However, α, β, and γ are first-order, second-order, and third-order temperature coefficients, respectively, and T ₀ is a reference temperature (for example, 25 ° C.). Here, if the slope of the temperature characteristic curve at room temperature of 25 ° C. is flat, the fluctuation of the main vibration frequency due to the temperature change becomes small. The slope of this temperature characteristic curve is 1
Depends on the next temperature coefficient α.

The main factors that determine the primary temperature coefficient α are the cut angle of the piezoelectric substrate and the length in the X direction (see FIG. 1). For example, when the cut angle is decreased, the primary temperature coefficient α increases and the slope of the temperature characteristic curve also increases as shown in FIG. Further, as the length in the X direction becomes longer, the primary temperature coefficient α increases, and the slope of the temperature characteristic curve also increases as in the case of FIG. However, after forming the piezoelectric vibrating piece,
The cut angle and the length in the X direction cannot be corrected.
Therefore, the piezoelectric vibrating reed whose actual force value greatly differs from the target primary temperature coefficient α is selected and discarded. Therefore, useless cost was generated.

It is an object of the present invention to provide a method for adjusting the frequency of a piezoelectric vibrating piece, focusing on the above problems and enabling simultaneous adjustment of the frequency and temperature characteristics. It is another object of the present invention to provide a piezoelectric vibrating reed and a piezoelectric vibrating reed device having a constant frequency temperature characteristic. Another object of the present invention is to provide a method for adjusting the frequency of a piezoelectric vibrating piece, which can reduce the manufacturing cost.

[0007]

The present invention shows a phenomenon similar to that the length of the piezoelectric substrate in the X direction is apparently shortened due to the concentration of energy in the portion where the excitation electrode is formed. It is based on the knowledge that the number of energy sources is reduced and the degree of energy concentration is increased as the thickness of the excitation electrode is increased.

In order to achieve the above object, the method of adjusting the frequency of the piezoelectric vibrating piece according to the invention of claim 1 is to add the fine adjustment film to the central portion of the surface of the excitation electrode of the thickness-shear piezoelectric vibrating piece to provide the piezoelectric vibration. The main vibration frequency of the piece is lowered, and at the same time, the primary temperature coefficient in the frequency-temperature characteristic of the piezoelectric vibrating piece is reduced. That is, if a fine adjustment film is added to the central part of the surface of the excitation electrode, the degree of energy concentration increases and the length of the piezoelectric substrate in the X direction is apparently shortened, and the reduction of the primary temperature coefficient is promoted. This allows simultaneous adjustment of frequency and temperature characteristics.

Further, in the frequency adjusting method for a piezoelectric vibrating piece according to the invention of claim 2, the main vibration frequency of the piezoelectric vibrating piece is increased by adding a fine adjustment film to the peripheral portion of the surface of the excitation electrode of the thickness shear vibrating piece. At the same time as lowering, it is configured to suppress the decrease of the primary temperature coefficient in the frequency-temperature characteristic of the piezoelectric vibrating piece. That is, if the fine adjustment film is added to the peripheral portion of the surface of the excitation electrode, the degree of energy concentration is reduced, the length of the piezoelectric substrate in the X direction is apparently increased, and the decrease of the primary temperature coefficient is suppressed. This allows simultaneous adjustment of frequency and temperature characteristics.

According to a third aspect of the present invention, there is provided a piezoelectric vibrating reed frequency adjusting method, wherein an electrode material is removed from a central portion of a surface of an excitation electrode of the thickness-shear piezoelectric vibrating reed.
At the same time as increasing the main vibration frequency of the piezoelectric vibrating piece,
The piezoelectric vibrating piece is configured to promote the increase of the primary temperature coefficient in the frequency-temperature characteristic. That is, if the electrode material is removed from the central portion of the surface of the excitation electrode, the length of the piezoelectric substrate in the X direction is apparently increased, and the increase of the primary temperature coefficient is promoted. This allows simultaneous adjustment of frequency and temperature characteristics.

According to a fourth aspect of the present invention, there is provided a method for adjusting a frequency of a piezoelectric vibrating reed, wherein an electrode material is removed from a peripheral portion of a surface of an exciting electrode of the thickness-shear piezoelectric vibrating reed.
At the same time as increasing the main vibration frequency of the piezoelectric vibrating piece,
The piezoelectric vibrating reed is configured to suppress an increase in the primary temperature coefficient in the frequency-temperature characteristic. That is, if the electrode material is removed from the peripheral portion of the surface of the excitation electrode, the length of the piezoelectric substrate in the X direction is apparently shortened, and the increase of the primary temperature coefficient is suppressed. This allows simultaneous adjustment of frequency and temperature characteristics.

In the method of adjusting the frequency of the piezoelectric vibrating piece according to the fifth aspect of the present invention, the peripheral portions are both end portions in the X direction of the crystal axis of the piezoelectric vibrating piece. Thereby, the manufacturing process can be simplified and the manufacturing cost can be reduced. In the method of adjusting the frequency of the piezoelectric vibrating piece according to the invention of claim 6, the electrode material is removed by a laser. A more effective fine adjustment effect can be aimed at because the electrode films on the front and back surfaces can be removed by laser irradiation from one surface. Further, the manufacturing process is simplified and the manufacturing cost can be reduced. Also,
It is possible to remove the electrode material even after mounting the piezoelectric vibrating piece.
It is possible to provide a highly accurate piezoelectric vibrating piece.

On the other hand, the piezoelectric vibrating piece according to the invention of claim 7 is configured to be manufactured by using the frequency adjusting method of the piezoelectric vibrating piece according to any one of claims 1 to 6. This makes it possible to provide a piezoelectric vibrating piece having a constant frequency temperature characteristic.

On the other hand, the piezoelectric device according to the invention of claim 8 has a structure manufactured by using the piezoelectric vibrating piece according to claim 7. This makes it possible to provide a piezoelectric device having a constant frequency temperature characteristic.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a frequency adjusting method for a piezoelectric vibrating piece, a piezoelectric vibrating piece and a piezoelectric device according to the present invention will be described in detail with reference to the accompanying drawings. Note that the description below is only one mode of the embodiment of the present invention,
The present invention is not limited to these.

The present invention is based on the following knowledge regarding frequency characteristics and temperature characteristics of the AT-cut quartz crystal resonator element. Note that FIG. 1 shows a definition diagram of crystal axes and external dimensions of the AT-cut quartz crystal resonator element. The AT-cut crystal vibrating piece is defined by the XZ plane at the crystal axis (X, Y, Z) of the crystal.
It is assumed that a plane rotated by an angle θ about the X axis is cut out from the crystal along this plane. By rotating the Y and Z axes by an angle θ around the X axis, the crystal axis of the AT-cut quartz crystal vibrating piece is defined by (X, Y ′, Z ′).

First, the main vibration frequency f _I of an infinite flat crystal plate is expressed by the following equation.

[Equation 2] Here, A is a frequency constant and is represented by the following equation.

[Equation 3] However, C ₆₆ is an elastic constant and ρ is the density of the crystal. In addition, the main vibration frequency f of the finite plate of quartz
_L is represented by the following equation.

[Equation 4] However, C ₁₁ is an elastic constant. As shown in Equation 4,
The main vibration frequency f _L of the finite flat plate is affected by the length a in the X direction. Generally, since the second term in the braces of Formula 4 is very small, the main vibration frequency f _L of the finite plate is
It becomes almost equal to the main vibration frequency f _I of the infinite plate.

Further, the main vibration frequency f _P when an electrode is formed on an infinite flat plate is expressed by the following equation.

[Equation 5] However, t _s is the thickness (2b) of the crystal, t _e is the thickness of the electrode, ρ _e is the density of the electrode, and ρ is the density of the crystal. From Equation 5, it can be seen that the main vibration frequency f _P is determined by the thickness of the crystal and the thickness of the electrode. The fluctuation of the main vibration frequency f _P also occurs due to the fluctuation of the crystal thickness and the electrode thickness.

On the other hand, FIG. 2 shows a graph of frequency temperature characteristics of an AT-cut quartz infinite plate. As shown in FIG. 2, the frequency-temperature characteristic has a cubic curve and is generally expressed by the following equation.

[Equation 6] However, α, β, and γ are first-order, second-order, and third-order temperature coefficients, respectively, and T ₀ is a reference temperature (for example, 25 ° C.). Here, if the slope of the temperature characteristic curve at room temperature of 25 ° C. is flat, the fluctuation of the main vibration frequency due to the temperature change becomes small. The slope of this temperature characteristic curve is 1
It depends on the next temperature coefficient α. The main factor that determines the primary temperature coefficient α is the cut angle of the quartz substrate. For example, the cut angle θ is from 35 ° 21 'to 35 ° 1
When it is decreased to 2 ', the primary temperature coefficient α increases, and
As shown in, the slope of the temperature characteristic curve also increases. In the case of a finite flat plate, the length of the crystal substrate in the X direction is also a major factor in determining the slope of the temperature characteristic curve. That is,
If the length in the X direction becomes longer, the primary temperature coefficient α increases,
As in the case of FIG. 2, the slope of the temperature characteristic curve also increases.

By the way, when an electrode is formed on a quartz substrate, the concentration of excitation energy is generated at that portion, which causes a phenomenon similar to that in which the length of the quartz substrate in the X direction is apparently shortened. The secondary temperature coefficient α decreases. Then, as the thickness of the formed electrode increases, the degree of energy concentration also increases. By utilizing this, the main vibration frequency and the frequency temperature characteristic of the thickness-sliding quartz crystal vibrating piece can be adjusted at the same time.

First, a fine adjustment film (for example,
A case of forming a thin film of Ag / Cr, Au / Ag, Ag, Al or the like to adjust the main vibration frequency will be described. When the fine adjustment film is added in this way,
Since s increases, the main vibration frequency f _P decreases. Here, a plurality of crystal vibrating pieces in which the fine adjustment films are formed at different positions are created. That is, in addition to the one in which the fine adjustment film is uniformly formed on the entire surface of the excitation electrode as in the conventional case, the fine adjustment film is formed only in the central portion 12 of the excitation electrode 10 as shown in FIG. 3 (1). , And the excitation electrode 1 as shown in FIG.
A fine adjustment film is formed only on the peripheral portion 14 of 0. The main vibration frequencies are shown in Table 1, and the frequency temperature characteristics are shown in FIG.

[Table 1] From Table 1, it can be seen that the frequency is adjusted to be equal regardless of the position where the fine adjustment film is formed.

On the other hand, it can be seen from FIG. 4 that the slope of the temperature characteristic curve at room temperature of 25 ° C. differs depending on the position where the fine adjustment film is formed. This is because the degree of energy concentration increases due to the addition of the fine adjustment film, so that the X-direction length of the crystal vibrating piece apparently becomes shorter than that before the frequency adjustment, and the temperature characteristic curve before the frequency adjustment. The slope of any of the temperature characteristic curves is smaller than the slope of. On the other hand, when the fine adjustment film is formed only in the central portion, the energy concentration becomes large in the central portion, so that the apparent X-ray density is higher than in the case where the fine adjustment film is uniformly formed over the entire surface.
The direction length becomes shorter. Therefore, the slope of the temperature characteristic curve is particularly small. Further, when the fine adjustment film is formed only on the peripheral portion, the excitation energy is dispersed,
The apparent length in the X direction becomes longer than in the case where the fine adjustment film is uniformly formed over the entire surface. Therefore, the slope of the temperature characteristic curve is not so small.

Next, the case where the electrode material is removed from the surface of the excitation electrode to adjust the main vibration frequency will be described. When the electrode material is removed in this manner, ts in Expression 5 decreases, so the frequency f _P increases. here,
A plurality of quartz crystal vibrating pieces in which the electrode material is removed from different positions are prepared. That is, as in the conventional case, in addition to the case where the electrode material is uniformly removed from the entire surface of the excitation electrode,
As shown in (1), the electrode material was removed only from the central portion 12 of the excitation electrode 10, and the electrode material was removed from only the peripheral portion 14 of the excitation electrode 10 as shown in FIG. 3 (2). To do. These main vibration frequencies are shown in Table 2, and the temperature characteristic curve is shown in FIG.

[Table 2] It can be seen from Table 2 that the same frequency can be adjusted regardless of the position where the electrode material is removed.

On the other hand, FIG. 5 shows that the slope of the temperature characteristic curve differs depending on the position where the electrode material is removed. This is because the energy concentration is reduced by removing the electrode material, and therefore the length of the crystal vibrating piece in the X direction is apparently longer than that before the frequency adjustment. The slope of any of the temperature characteristic curves is larger than the slope of. On the other hand, when removed only from the peripheral portion, energy concentration remains in the central portion, so compared with the case where it is removed uniformly from the whole,
The apparent X-direction length becomes shorter. Therefore, the slope of the temperature characteristic curve is not so large. Further, since the excitation energy is dispersed when the film is removed only from the central portion, the apparent length in the X direction becomes conversely longer than in the case where the film is uniformly formed on the entire surface. As a result, the slope of the temperature characteristic curve becomes particularly large.

In FIG. 3B, the fine adjustment film is formed and the electrode material is removed from the entire peripheral portion 14 of the excitation electrode 10. However, it contributes to the slope of the temperature characteristic curve as described above. Is mainly the apparent length of the quartz crystal vibrating piece in the X direction. Therefore, as shown in FIG. 6, the fine adjustment film may be added and the electrode material may be removed only on the peripheral portion 15 of the excitation electrode 10 in the X direction. FIG. 7 shows a temperature characteristic curve when the electrode material at the peripheral portion in the X direction is removed.
As described above, when the electrode material is removed from the peripheral portion, the energy concentration remains in the central portion, so that the apparent length in the X direction becomes shorter than in the case where the electrode material is uniformly removed from the whole. Therefore, even when the electrode material in the peripheral portion in the X direction is removed, the slope of the temperature characteristic curve is smaller than that in the case where the electrode material is uniformly removed from the whole.

Next, a specific method of using the method of adjusting the frequency of the crystal resonator element according to this embodiment will be described. FIG. 8 shows a flowchart of the method for adjusting the frequency of the crystal resonator element according to the present embodiment. First, the finish frequency of the formed crystal vibrating piece is measured (S70). Next, the frequency-temperature characteristic of the formed quartz crystal vibrating piece is measured (S72). In the measurement of the frequency-temperature characteristic, one point above and below room temperature 25 ° C. is set as the measurement temperature, the main vibration frequency at these temperatures is measured, and the slope of the temperature characteristic curve at room temperature 25 ° C. is estimated.

Next, the measured frequency at room temperature is compared with the target frequency (S74). When it is determined that the measured frequency is higher than the target frequency, frequency adjustment is performed by forming a fine adjustment film on the surface of the excitation electrode, as described below. The fine adjustment film is formed by a vacuum vapor deposition method or the like. The vacuum evaporation method is a method of forming a thin film by heating and evaporating a fine adjustment film material in a vacuum and attaching it to the surface of the excitation electrode. As the fine adjustment film material, the same Ag / Cr material as the excitation electrode material of the quartz crystal vibrating piece is used. When forming a fine adjustment film only on a specific position on the surface of the excitation electrode, create a mask that has a transparent part of the fine adjustment film material only on the part where the film is formed. A vapor deposition method etc. are implemented.

Next, in order to determine the formation position of the fine adjustment film,
The slope of the temperature characteristic curve obtained by the measurement is compared with the target slope of the temperature characteristic curve (S76). Then, when the inclination obtained by the measurement is larger than the target inclination, the fine adjustment film is formed only in the central portion of the excitation electrode (S8).
0). As a result, the main vibration frequency can be matched with the target value, and the slope of the temperature characteristic curve can be matched with the target value. If the inclination obtained by the measurement is smaller than the target inclination, the fine adjustment film is formed only on the peripheral portion of the excitation electrode (S82). This makes it possible to match the frequency with the target value and suppress the decrease in the slope of the temperature characteristic curve.

When the inclination obtained by the measurement is slightly larger than the target inclination, if the fine adjustment film is formed only in the central portion of the excitation electrode, the inclination may be less than the target inclination. In this case, a fine adjustment film may be formed slightly on the entire excitation electrode as in the conventional case, or a small adjustment film may be formed only on the peripheral portion of the excitation electrode.

On the other hand, when it is determined in step 74 that the measured frequency is lower than the target frequency, the frequency is adjusted by removing the electrode material from the surface of the excitation electrode, as described below. The electrode material is removed by a sputtering method or the like. The sputtering method is a method in which accelerated particles such as ions are made to collide with an excitation electrode, and atoms near the surface of the excitation electrode, which have obtained part of the momentum of the particles, are knocked out into space and removed. When removing the electrode material only from a specific position on the surface of the excitation electrode, create a mask that has a permeable portion for accelerated particles only at the position to be removed, attach it to a quartz resonator element, and then perform the sputtering method. To do.

Instead of the sputtering method, a laser may be used to remove the electrode material. Even when the laser is disposed on the front surface side of the crystal vibrating piece, the electrode material can be removed from the excitation electrode formed on the back surface side of the crystal vibrating piece by changing the depth of focus. Thus, the frequency of the crystal vibrating piece can be adjusted even after the crystal vibrating piece is mounted on a package or the like. That is,
The frequency shift accompanying the mounting of the crystal vibrating piece can be eliminated after the mounting, and the crystal vibrating piece with high accuracy can be provided.

Next, in order to determine the removal position of the electrode material, the slope of the temperature characteristic curve obtained by the measurement is compared with the target slope of the temperature characteristic curve (S84). Then, when the inclination obtained by the measurement is smaller than the target inclination, the electrode material is removed only from the central portion of the excitation electrode (S86). This makes it possible to match the frequency with the target value and the slope of the temperature characteristic curve with the target value. If the inclination obtained by the measurement is larger than the target inclination, the electrode material is removed only from the peripheral portion of the excitation electrode (S88). This makes it possible to match the frequency with the target value and suppress an increase in the slope of the temperature characteristic curve.

If the inclination obtained by the measurement is slightly smaller than the target inclination, removing the electrode material only from the central portion of the excitation electrode may exceed the target inclination. In this case, the electrode material may be slightly removed from the entire excitation electrode as in the conventional case, or the electrode material may be slightly removed from only the peripheral portion of the excitation electrode.

The crystal vibrating piece whose frequency has been adjusted as described above can be used as a crystal resonator by enclosing it in a package. FIG. 9 shows an explanatory view of the crystal unit. 1A is a plan sectional view taken along line EE, and FIG. 2B is a side sectional view taken along line DD. In the crystal unit 1 of FIG. 9, the package 7 is formed of a ceramic material or the like. Further, an electrode 9 and a wiring pattern (not shown) are formed on the bottom surface of the cavity 4,
Conduction is possible with external terminals (not shown) formed on the back surface of the package 7. Then, the crystal vibrating piece 3 is mounted in a cantilever state. Specifically, the conductive adhesive 2 is formed on the electrode 9.
Is applied, and the connection electrode 18 of the crystal vibrating piece 3 is arranged and fixed thereon. As a result, the excitation electrodes 10 of the crystal vibrating piece 3 can be energized from the external terminals on the bottom surface of the package 7. A lid member 5 is attached to the upper part of the package 7 to maintain the inside of the package 7 in a nitrogen atmosphere or the like.

The crystal vibrating piece according to the present embodiment can be used as a crystal oscillator by forming an oscillation circuit in combination with an integrated circuit element. For example,
A crystal oscillator module can be formed by mounting the crystal unit 1 and the integrated circuit element (not shown) shown in FIG. 9 on a module substrate on which a wiring pattern is formed. Further, by enclosing the integrated circuit element together with the crystal vibrating piece 3 in the package 7 shown in FIG.
Further, a smaller crystal oscillator can be formed.

As described above, according to the method of adjusting the frequency of the crystal resonator element according to the present invention, the temperature characteristics can be adjusted at the same time, and the cost can be reduced. In this respect, conventionally, when the slope of the temperature characteristic curve of the formed quartz crystal vibrating piece is significantly different from the target temperature characteristic curve at room temperature of 25 ° C., this is selected and discarded. . Therefore, useless cost was generated.

However, in the method of adjusting the frequency of the quartz resonator blank according to the present invention, the frequency is adjusted by setting the position where the fine adjustment film is added or the position where the electrode material is removed as the central portion or the peripheral portion of the surface of the excitation electrode. As a result, the main vibration frequency can be lowered or raised, and at the same time, the decrease or increase of the primary temperature coefficient in the frequency-temperature characteristic can be promoted or suppressed. Therefore, the frequency of discarding the crystal vibrating piece due to poor temperature characteristics is reduced, and wasteful cost can be reduced.

The present invention is based on the knowledge of the AT-cut quartz crystal vibrating piece, but is not limited to BT, FC, IT,
It can also be applied to thickness-shear vibrating bars other than AT-cut, such as SC-cut.

[0039]

EFFECT OF THE INVENTION By adding a fine adjustment film to the central portion of the surface of the excitation electrode of the thickness-shear piezoelectric vibrating piece, the main vibration frequency of the piezoelectric vibrating piece is lowered, and at the same time, the primary temperature frequency characteristic of the piezoelectric vibrating piece is reduced. It is configured to accelerate the decrease of the temperature coefficient. Further, by adding a fine adjustment film to the surface peripheral portion of the excitation electrode of the thickness-shear piezoelectric vibrating piece, the main vibration frequency of the piezoelectric vibrating piece is lowered, and at the same time, the primary temperature coefficient of the frequency-temperature characteristic of the piezoelectric vibrating piece is reduced. It is configured to suppress the decrease. In addition, by removing the electrode material from the central portion of the surface of the excitation electrode of the thickness-shear piezoelectric vibrating piece, the main vibration frequency of the piezoelectric vibrating piece is increased, and at the same time, the primary temperature coefficient of the frequency-temperature characteristic of the piezoelectric vibrating piece is increased. It is configured to promote the increase. Further, by removing the electrode material from the surface peripheral portion of the excitation electrode of the thickness-shear piezoelectric vibrating piece, the main vibration frequency of the piezoelectric vibrating piece is increased, and at the same time, the primary temperature coefficient of the frequency temperature characteristic of the piezoelectric vibrating piece is increased. It is configured to suppress the increase. These allow simultaneous adjustment of frequency and temperature characteristics.

[Brief description of drawings]

FIG. 1 is a definition diagram of crystal axes and external dimensions of an AT-cut quartz crystal resonator element.

FIG. 2 is a temperature characteristic curve diagram of an AT-cut quartz infinite plate.

FIG. 3 is an explanatory diagram of a fine adjustment film forming position and an electrode material removing position on the excitation electrode surface, where (1) is a central portion and (2) is a peripheral portion.

FIG. 4 is a temperature characteristic curve diagram when a frequency is adjusted by forming a fine adjustment film.

FIG. 5 is a temperature characteristic curve diagram when the frequency is adjusted by removing the electrode material.

FIG. 6 is an explanatory diagram of a peripheral portion in the X direction on the surface of the excitation electrode.

FIG. 7 is a temperature characteristic curve diagram when the electrode material at the peripheral portion in the X direction on the excitation electrode surface is removed.

FIG. 8 is a flowchart of a method for adjusting the frequency of the quartz crystal resonator element according to the embodiment.

FIG. 9 is an explanatory diagram of a crystal unit, (1) is EE
It is a plane sectional view in a line, and (2) is a side surface sectional view in a DD line.

[Explanation of symbols]

1 ... Piezoelectric vibrator, 2 ... Conductive adhesive, 3 ...
Piezoelectric vibrating piece, 4 ... Cavity, 5 ... Lid member, 7
……… Package, 9 ……… Electrode, 10 ……… Exciting electrode, 12 ……… Center part, 14 ……… Peripheral part, 15 ………
Peripheral portion in X direction, 18 ... Connection electrode.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuji Kitahara             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -Epson stock company F term (reference) 5J108 AA04 BB02 CC04 DD02 EE03                       EE04 EE07 FF03 FF11 GG03                       HH04 KK06 KK07 NB05

Claims (8)

[Claims] 1. A main vibration frequency of the piezoelectric vibrating piece is lowered by adding a fine adjustment film to the central portion of the surface of the excitation electrode of the thickness-shear piezoelectric vibrating piece, and at the same time, the primary temperature frequency characteristic of the piezoelectric vibrating piece is reduced. A frequency adjusting method for a piezoelectric vibrating piece, which is characterized by promoting a decrease in temperature coefficient. 2. A main vibration frequency of the piezoelectric vibrating piece is lowered by adding a fine adjustment film to the peripheral edge portion of the surface of the excitation electrode of the thickness-shear piezoelectric vibrating piece, and at the same time, the primary temperature frequency characteristic of the piezoelectric vibrating piece is reduced. A frequency adjusting method for a piezoelectric vibrating piece, which is characterized by suppressing a decrease in temperature coefficient. 3. The main vibration frequency of the piezoelectric vibrating piece is increased by removing the electrode material from the center of the surface of the excitation electrode of the thickness-shear piezoelectric vibrating piece, and at the same time, the primary temperature frequency characteristic of the piezoelectric vibrating piece is increased. A frequency adjusting method for a piezoelectric vibrating piece, which is characterized by promoting an increase in temperature coefficient. 4. The main vibration frequency of the piezoelectric vibrating piece is increased by removing the electrode material from the peripheral edge portion of the surface of the excitation electrode of the thickness-shear piezoelectric vibrating piece, and at the same time, the primary temperature frequency characteristic of the piezoelectric vibrating piece is increased. A method for adjusting a frequency of a piezoelectric vibrating piece, which suppresses an increase in temperature coefficient. 5. The method for adjusting the frequency of a piezoelectric vibrating piece according to claim 2, wherein the peripheral portion is both end portions in the X direction of the crystal axis of the piezoelectric vibrating piece. 6. The frequency adjusting method for a piezoelectric vibrating piece according to claim 3, wherein the electrode material is removed by a laser. 7. A piezoelectric vibrating piece manufactured by using the frequency adjusting method for a piezoelectric vibrating piece according to claim 1. Description: 8. A piezoelectric device manufactured by using the piezoelectric vibrating piece according to claim 7.