JPS5833308A - Coupled quartz oscillator - Google Patents

Abstract

PURPOSE:To obtain a titled oscillator having a small primary temperature coefficient, by providing exciting electrodes at the entire area of upper and lower surfaces of the oscillating part of said oscillator and setting larger thickness for the electrode at the edge part in the width direction that decides the resonance frequency of the main oscillation than the electrode at the cener part. CONSTITUTION:Exciting electrodes 33 and 34 are provided on the entire surface of an oscillating part 35 on both upper and lower surfaces 31 and 32 of a coupled oscillator 30 of GT-cut in which plural vertical oscillation modes are combined. The part 35 and the supporting parts across the part 35 are formed in a body. The electrodes 20 and 21 at the edge part in the width direction that decides the resonance frequency of the main oscillation of the electrode 33 have larger thickness than an electrode 36 at the center part. The thickness is controlled for the electrodes 20 and 21 by means of the vapor deposition of Au, Ag, etc. As a result, the primary temperature coefficient is approximately zero and the crystal impedance value is reduced with no spurious oscillation for a coupled oscillator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention applies to an excitation electrode of a so-called coupled crystal resonator in which a plurality of longitudinal vibration modes are coupled.

An object of the present invention is to provide a coupled crystal resonator with excellent frequency characteristics (hereinafter referred to as temperature characteristics).

Another object of the present invention is to provide a coupled quartz crystal with small ox (Orystal engineering). Excellent thermal properties, strength%b
There are many consumer devices that require small oscillators,
These K1-1 T-cut crystal resonators were used.

However, recently, various consumer devices have become smaller, and whip-cut crystal resonators have also been required to be smaller.
The reality is that it is difficult to make the cap smaller, and at the same time, the 0 min becomes higher when the cap is made smaller. aK needs to be made smaller, and when compared with a tuning fork type bent crystal resonator, it is not completely satisfactory in terms of size. Therefore, recently, a method of forming a vibrator using photolithography, which applies the above 10 techniques, has been applied to the manufacture of vibrators, and as a result, it has become possible to provide extremely small vibrators. For example, it has been applied to T-cut crystal oscillators with excellent temperature If% properties that allow the thickness of the oscillator to be made very thin, making it possible to create very thin oscillators.

However, these zero-cut crystal resonators have two vibration modes, i.e., main vibration and iI
It uses the coupling of l vibrations. Therefore, the temperature characteristic is determined by the difference in the resonance frequency between the main vibration and the sub-vibration. Theoretically, it is possible to determine the difference in resonant frequency that provides excellent temperature [41], but in reality, due to manufacturing variations, it is difficult to maintain a constant temperature.
Characteristic para.

It was the cause of the trouble. Several methods have been proposed to absorb variations in the temperature characteristics of kernels. For example,
-5508, the excitation electrode is removed and the temperature WLIfIi4 is
Although a method of adjusting & is proposed, since the excitation electrode t# is removed, the actual field efficiency decreases, resulting in a problem that the aX value increases. It also states that the frequency can be fine-tuned by changing the thickness of the electrode film by vapor deposition, but there is no specific explanation of how to do this. Because of the support, it was difficult to miniaturize, and at the same time, it had the disadvantage of being weak against shock.

Therefore, the present invention has improved these problems and drawbacks, that is, improved the supporting method, and discovered and improved a new method for adjusting temperature characteristics and a new method for adjusting resonant frequency. The present invention will be described in detail below with reference to the drawings.

Figure 1 shows an embodiment of the shape and electrodes of a coupled resonator according to the present invention, in which a vibrating part 2 and two supporting parts 5 disposed on both sides thereof are integrally shaped like a KG-cut crystal resonator. This is an example. FIG. 1(M) shows a plan view, and FIG. 1(B) shows a side view. On the upper surface 4 and lower surface 5 of the vibrating part 2 of the crystal 1, excitation electrodes @6 and 7 are arranged uniformly over the entire surface, the excitation electrode 6 is arranged extending to one of the supporting parts 3, and the excitation electrode 7 is arranged to extend from the other support portion SVc. That is, the support part has a structure in which electrodes are arranged only on one side and no electric field is applied. Therefore, this confines the energy of the vibrating part as much as possible inside the vibrating part and prevents it from being transmitted to the support part. In other words, from the vibrating part 2 to the supporting part 3
The electrode extending to is just a hook electrode necessary for applying an electric field. By applying an alternating voltage to both electrodes extending to the support part 3, the vibrator can be easily excited. Iro.

Also, the resonance frequencies of the two modes are determined by the width W and the length L, and the resonance frequency f of the main vibration is determined by the width W#IC.
The reason why the excitation electrodes are arranged on the upper and lower surfaces of the vibration s2 and the entire surface of the vibration s2 will be explained.

FIG. 2(M) is a diagram A of a GT cut crystal resonator in which the vibrating section 2 and the supporting section 5 of the present invention are integrally formed. °
It shows the calculated value of the relationship between each position of the cross-sectional muum and the displacement. That is, the displacement becomes zero at point C, and from point C to point a
, e is a vibration in which the absolute value of displacement increases as it goes to e (displacement u = -ul). Figure 2 (B) shows the relationship between strain and each position. That is, the distortion becomes maximum at point C and decreases toward the end. However, as clearly shown in FIGS. 2 and 3, the distortion does not become zero at the ends a and e, and distortion occurs. This means that the zero-factor value of the crystal resonator is different depending on whether or not an excitation electrode is disposed at the end of the vibrating section. That is,
A low OX value can be obtained by arranging the excitation electrode in a trench at the end of the **-.

FIG. 5 is a histogram of the distribution of 0 man-hours when the excitation electrodes are placed on the entire top and bottom surfaces of the vibrating part, and when they are placed in the part (approximately 7s- of the II part), which is an experimental value. Figure 5 (A) shows the number of excitation electrodes arranged in a section, n=2.
This is a histogram showing the distribution of CI values relative to 00, and the average value is z m 14 Q (c). On the other hand, the third
Figure (B) is a histogram showing the distribution of CI values when the number of pieces is nxx 2Q Q when they are arranged on the upper and lower surfaces of the vibrating part, and the entire surface. It can be seen that the excitation electrodes are arranged on the entire surface, and the effect when using holes is significantly large.

FIG. 4 shows the 0-cut crystal resonator 9 of the present invention on a support stand 8.
In one embodiment, when mounted on a top view (M) and a side view (B), shown in FIG. Alternatively, it is fixed by soldering. Excitation electrodes 10°11 are arranged on the upper and lower surfaces of the crystal resonator. crystal 11
! Since the pin 9Fi is fixed to the support base 8 at both ends, it is possible to provide a crystal resonator with excellent impact resistance. Furthermore, although the crystal resonator 9 has a complicated shape, it can be easily formed by photolithography. As a result - it is now possible to provide a very compact quartz crystal. Next, the temperature f% property will be explained.

The following relationship exists between the resonance frequency fW of the main vibration due to the width W and the resonance frequency fI- of the sub-vibration due to the length LK.

flcc-・・・・・・・・・・・・・・・ (1) f
X, E- (2) Furthermore, the temperature characteristics are almost determined by the difference fW-fL between both resonance frequencies.

The @S diagram is an example of the ( ) T-cut crystal resonator oia * characteristics q) of the present invention formed by photolithography, and the temperature f%! ! It will be 11P. When the coupling between the main vibration and the sub-vibration is weak, i.e., when δ= and mardeci is large, it looks like a straight tortoise, and when the coupling is strong, i.e.
When - is small, it becomes a straight line. At this time, the absolute value of the −th temperature coefficient α is very hot, about 2.5×10−・7℃, and the temperature I [%] that meets the horizontal foot is expressed as %, but when − is the optimal value, it is a straight line. It becomes like C, and shows the characteristics of Arashiyoshi & l1 degree.

Generally made coupled oscillators exhibit the following) Those with negative values, on the other hand, like the direct Ilb, α force; approximately +2
．． Those with a positive value of 5X10-・7℃, and
Straight line C, where a is almost zero, shows a wide variety of temperature II characteristics, and α of the resonator after formation is -2,
It is within the range of 5×10−·/°C to +15×10=/U. Here, the fact that α is positive, negative, or almost zero is defined as follows.

(1) The fact that the -order temperature coefficient α is almost zero means that a is within −tOX10−ma/°C.

(2) The −th temperature coefficient a is positive, which means that α is α)
t OX 1 o-? Say what is in /c.

(3) The −th order concealment coefficient a is negative, which means that a is α(−t
What is at ox1o″1/°C 1- Say.

Figure 4 shows an example of the GT-cut crystal resonator of the present invention. I) On the upper surface 15 and lower surface 16 (not shown) of the ils 14, excitation electrodes 17 and 18 (not shown) are uniformly arranged over the entire surface, and the excitation electrode arranged on the upper surface 15 Electrodes 20 and 21, which are thicker than the central electrode 19, are symmetrically arranged by vapor deposition at the ends of the electrodes 17 in the width W direction and at approximately the center in the thickness direction. Placing the electrodes in the inner part of the vibrating part thickly has the following three effects.

(1311kllJ@ Increasing the thickness of the excitation electrode at the end has an electrode loading effect, that is, it acts as a weight. Therefore, the resonance frequency f1 and temperature characteristics can be changed.

At the same time, -1 (2) Due to the electrode load effect, it is possible to reduce the reflection of elastic waves at the ends of the vibrating wh section and suppress spurious vibrations.

(3) Due to the electrode loading effect, excitation energy can be trapped inside m1ss. Therefore, the zero work value can be further lowered.

Figure 7 shows the change in the primary temperature coefficient α with respect to the amount of electrode added when the electrodes 20 and 21 in Figure 6 are made thicker by vapor deposition.
It shows. That is, as the excitation electrodes 20.degree. 21 become thicker, the -subtemperature coefficient a moves toward the negative side.

Fig. 8 Fi is another embodiment of the G'r cut crystal resonator of the present invention, with electrodes 22.25°24.2 by vapor deposition at the four corners.
This is an example in which 5 is attached.

FIG. 9 shows the relationship between the first-order temperature coefficient α and the amount of electrode deposition when the electrodes 22.25 and 24.25 of FIG. 8 are deposited and thickened by vapor deposition. As the amount of electrode deposition increases, - The next temperature coefficient aFi moves to the positive side. As can be seen from the above, in the case of the electrode shown in Fig. 6, by attaching the end electrode, 1. By attaching the electrodes, the -order temperature coefficient α moves to the negative direction, and as shown in FIG. 6, by attaching the electrodes, the -order temperature coefficient α moves to the positive side. That is, the southern electrode 20.21 in FIG. 6 and the southern electrode 2 in FIG.
When the electrode is attached between 2, 25, 24.25, -
It can be predicted that the next temperature coefficient α will not change at all.

FIG. 10 shows another embodiment of the electrode attachment of the GT-cut crystal resonator of the present invention, in which the electrode 20 in FIG. 6 and the electrode 22 in FIG.
．． The thick electrode is between 25 and 26.2? is attached to the electrode 27 so that it is between the electrode 21 and the electrodes 25 and 24.
．． FIG.

@11tEIH1 1st o @Nogame 86% electrode 26,27゜2'8.29 is attached with a steam eyebrow, and the relationship between the first temperature coefficient α and the amount of electrode adhesion is shown. It can be seen that there is no change at all.

FIG. 12 shows electrodes 20 and 21 in FIG. 6 and electrode 2 in FIG.
2, 2! S, 24, 25, 10th WA electrode 26.27
．． 28.2? It shows the change in the resonant frequency of the raw material with respect to the amount of electrode deposited when each is deposited by vapor deposition, and the straight line, F
correspond to the cases of FIG. 6, FIG. 10, and FIG. 8, respectively. Even in such a case, it can be seen that the resonance frequency of the main vibration becomes lower depending on the amount of adhesion of the end electrode.

Next, the frequency adjustment and temperature f% adjustment method will be specifically explained.

The GT-cut crystal resonator shown in FIG. 1 is designed to have the following characteristics after being released by photography.

(1) The resonant frequency of the main vibration is the reference frequency f to be matched.
, have a higher value. Usually 11000pp~2000
ppm is high.

Such a vibrator can be easily obtained by selecting the shape and etching time. Next, this vibrator is placed at a certain arbitrary temperature, this temperature is read by a temperature needle such as a thermistor, and this temperature is set as tl. The resonance frequency ftl of the main vibration at this time is determined. Furthermore, place the vibrator at any other temperature, and then read the temperature [t'* of 1 in the same manner as above. Temperature j[ttets and resonant frequency f・, f.

The first-order temperature coefficient α is determined from the following equation.

a x b Niha (HM/℃) ・・・・・・= (3
) is rewritten using the standard frequency fo to match,
It will look like this:

f 鵞−fl 1 α−−−(1/℃)・・・・・・(4) f・ は−11 Figure 13 shows this situation, and the straight line g is an example when α is positive. . Temperature t@ is the resonant frequency of raw frying with reference frequency f
, is the temperature when adjusting to .

When the temperature is t, the resonant frequency f of raw frying is the standard frequency f.
It is higher than that. Therefore, the resonant frequency ft of raw air
-Reference frequency foK: There are three methods described above to adjust the thickness of the end electrode by increasing the thickness. However, in this case, since α is positive, α can be further reduced by adopting a method of moving α to the negative side. That is, this is a method in which the electrodes 20 and 21 shown in FIG. 6 are attached. 13 shows the change in temperature characteristics when adjusting to the straight line 1Fi, the resonance frequency ft and the reference frequency f·. As it approaches the reference frequency f, α approaches zero (straight line h),
When tuned to the standard frequency f, tk becomes almost zero (direct*i).

, 214 show an example of the temperature characteristics of the present invention obtained in this way. The straight line j shows the temperature characteristics after the resonator is formed, and the straight line j shows the temperature characteristics when the resonant frequency f of one vibration is adjusted to the reference frequency f, and the 1.5 ×10″″? /°C, which indicates good temperature characteristics. In exactly the same way, when α is negative, by adopting a method in which α moves to the positive side when adjusting the resonant frequency f of one vibration to the reference frequency f@, at- can be made even closer to zero. That is, this is a method in which the electrodes 22, 23, 24, and 25 shown in FIG. 8 are deposited thickly. Also, when α is almost zero, there is no need to change α, so there is a method in which α does not change when the resonant frequency f is adjusted to the reference frequency f. 29 may be used.

FIG. 15 shows a perspective view of an embodiment of the GT-cut crystal resonator of the present invention, showing an upper surface 31 and a lower surface 32 of the crystal resonator 30.
, excitation electrodes 55 and 54 are arranged on the entire surface of the vibration part 35, and the end electrodes 20 and 21 of the electrodes 53 are thicker than the center electrode s6.

By the way, in the present invention, Mu't Mug is used as a material for increasing the thickness of the electrode.

As described above, the present invention arranges excitation electrodes on the upper and lower surfaces and the entire surface of the vibrating part of a coupled resonator, and arranges the end electrodes in the width direction, which determine the resonance frequency of one vibration, thicker than the center electrodes. By providing a coupled resonator with a low Ox value and no spurious vibrations, the 11+ hole. Furthermore, we designed the oscillator to obtain the optimum temperature characteristics before adjusting the wave number of the coupled oscillator and the optimum resonance frequency of the main vibration, and set the oscillator to an arbitrary temperature tl.
, measure the resonance frequency ft, f of the main 11m at t@,
The first-order temperature coefficient a is calculated from this value, and the first-order temperature coefficient α is almost zero by vapor deposition, and the resonant frequency of one oscillation is tuned to f, which has excellent temperature characteristics.
Cut the crystal roots to make the crystal tube mover. Furthermore, the coupled vibrator of the present invention can be miniaturized because the vibrating part and the supporting part are integrally formed by photolithography.
Furthermore, since both ends of the support part of the vibrator are fixed with adhesive, soldering, etc., it is possible to provide a coupled vibrator with excellent impact resistance. Needless to say, the present invention can also be applied to a crystal resonator, for example, a two-cut crystal resonator.

[Brief explanation of drawings]

Figures 1 (4) and (2) are a plan view and a side view showing an embodiment of the shape and electrodes of the coupled resonator of the present invention, respectively, and show the vibrating part 2 and the two electrodes arranged on both sides thereof. This is an example of a Za-cut crystal resonator in which two supporting parts 3 are integrally formed. FIG. 2(4) is a half plan view of a zero-cut crystal resonator in which the swing l11 part 2 and the support part of the present invention are integrally formed. FIG. 2(9) is a graph showing the relationship between distortion and each position of the zero-cut crystal resonator of FIG. 2(4). FIG. 5(4) is a histogram of OOI values when the excitation electrode is placed in the area of oscillation am. Figure 3) is a histogram of Ox values when arranged on the upper and lower surfaces of the excitation electrode tube vibrating section and the entire surface. FIG. 4 shows the 0-cut crystal resonator 9 of the present invention on a support stand 8.
This is an example when mounted on the top view (4) and 11
w Figure (B) is shown. FIG. 5 is a graph showing an example of the temperature fIF# characteristic of the GT-cut crystal resonator of the present invention shaped by photolithography. The sixth WA is a plan view showing an example in which the electrodes are thickened by GT-based crystal oscillator deposition. FIG. 7 is a graph showing the change in the primary temperature coefficient α with respect to the amount of electrode added when the end electrode of FIG. 6 is thickened by vapor deposition. FIG. 8 is a plan view showing an embodiment in which electrodes are thickened by vapor deposition at the four corners of a GT-cut crystal vibrator. FIG. 9 is a graph showing the relationship between the first-order temperature coefficient α and the amount of electrode added when the end electrode of FIG. 8 is made thicker by vapor deposition. FIG. 10 is a plan view showing another embodiment in which the electrodes of the GT-cut quartz crystal are made thicker. Figure @11 is a graph showing the relationship between the first-order temperature coefficient a and the amount of electrode layer after the end electrode of Figure 10 is deposited by vapor deposition. FIG. 12 shows the end electrodes 20 e 21 in FIG. 8, the end electrodes 22, 25, 24, 25 in FIG. 8, and the end electrodes 24, 27, 28, 2? in FIG. It is a graph showing the change in the resonance frequency of the main vibration with respect to the electrode adhesion i1 when each thickness is increased by vapor deposition, and the graph is a straight line. F and F are respectively shown in Fig. 6 and Fig. 10111. This corresponds to the case shown in FIG. The straight line g in FIG. 15 is a graph showing the relationship between the resonant frequency of the earth scraper and the temperature of an oscillator with a positive temperature coefficient α. Shows the change in temperature when adjusted to FIG. 14 is a graph showing an example of nine temperature characteristics obtained by the present invention. FIG. 15 shows a perspective view of an embodiment of the GTT cut crystal resonator of the present invention. 20~2!・・・・・・Thick electrode or more Applicant: Daini Seikosha Co., Ltd. Representative Patent Attorney: Tsutomu Mogami Figure 1 (A) Figure 1 (B) Figure 4 (A
) Fig. 4 (8) Fig. 5 Fig. 6 Fig. 70 Fig. 8 Fig. 9 Fig. 1θ mouth Fig. 11 Fig. 12 Fig. 75 JE/ j< Z/ JG, lj
A Procedural amendment (method) l Indication of the case 1982 Patent Application No. 11011 2, Name of the invention Combined crystal oscillator 3, Relationship with the person making the amendment 4, Representative Director Hattori - Department 5 Date of amendment order, 62. Lines 4 to 2 from No. 19 of the Specification of Contents of Amendment: ``The direct IJg in Figure 13 is...a graph;
” and add the following sentence. ``Figure 13 is a graph showing the relationship between temperature and the resonant frequency of the vibrator main engine, and is a graph showing the relationship between temperature and the resonant frequency of the vibrator main engine.
An example is shown in which is positive, and 2″° above υ

Claims (1)

[Scope of Claims] (1) A coupled crystal resonator in which a plurality of longitudinal vibration electrodes are coupled, the vibrating part and the support part of the coupled crystal resonator are integrally formed, and the excitation electrode of the crystal resonator is Upper and lower surfaces of the vibrating part,
A coupled crystal resonator characterized in that one excitation electrode of the IITos is arranged over the entire surface and has a uniform thickness, while the other excitation electrode is thicker at the ends than at the center. (2. In claim (1), the excitation electrode on the lower surface is thick at at least one place near the center (20, 21) in the length direction at the end in the width direction of the vibrating part. (3) In claim (1), the excitation electrode on the lower surface is located at at least one of the four corners (24, 27, 28, 29) of the vibrating part. (4) In claim (1), the excitation electrode on the lower surface is located at the end of the vibrating part in the width direction, and has a length of There are 41 signs that at least one place between the center (2, 0, 21) and the four corners (26, 27, 28, 29) (22, 23, 24, 25) is thicker. (5) In paragraph (1) of the scope of claim 41, the excitation electrode on the lower surface is located at the end of the vibrating section in the width direction, near the center in the length direction (20, 21 ), the four corners of the vibrating part (26°27.2
8.29) At the end of the width direction of the vibrating part, at least in the vicinity of the center in the length direction (20, 21) and in the corners (22, 2N+, 24.25) of the four corners (26° 27.28.z?) If it is thicker in one place! Coupled crystal oscillator with I characteristic. (6) In paragraph (1) of the scope of claim 41, it is provided that the coupled crystal resonator is a GT cut crystal resonator.
Coupled crystal oscillator.