JPS58111515A - Crystal oscillator - Google Patents

Abstract

PURPOSE:To obtain a crystal oscillator having a cut azimuth with excellent resonance frequency versus temperature characteristics, by an angle phi in the range of -2.5 deg. to +35 deg., in turning an E type oscillator of the Z-cut around the X axis by the angle phi. CONSTITUTION:In an oscillator (E type oscillator) 61 where three oscillation branches are formed incorporatedly with the base of a crystal plate of uniform plate thickness, when the oscillator is turned around the Y axis from the state (Z-cut) that the branch width and length of the branch 62 are coincident with the X and Y axes of the crystal of an angle phi (the sign of phi is positive counter clockwise), the phi is set to the range from -2.5 deg. to +35 deg.. Metallic thin film electrodes 135, 136 are fixed to the side surface of the branches 131, 132, and 133, and a voltage having a frequency equal to the resonance frequency of the basic oscillation of the oscillator 130.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvement of the resonance frequency characteristics of a crystal sensor having three moving arms (hereinafter abbreviated as FE type resonator).

FIG. 1 is a diagonal hi diagram showing the external shape of an E-type vibrator according to the conventional technology and the present invention. Crystal machine ICi' with uniform root thickness! r< The cutting plates 11, 12.13 are integrally formed with the pace part 14, and the length dimensions of the three perturbation branches 11, 12.13 are as follows:
Evenly, branch width size/P:v stuck (1, vibration technique 11
．． 13 are almost equal to each other, and 1. The auxiliary plate 12 can be arbitrarily selected. FIGS. 2A and 2B are diagrams schematically showing the vibration modes of the E-type vibrator used in conventional and heather/bemei.

Figure 2 (A) shows 11. Figure g1 is a cross-sectional view of the 4-mode as seen from the YY analysis plane. Figure 2+B) is a sectional view of the vibration mode seen from the XX section in Figure 1 of the 4th edition. Vibration technique 11,1
2.13 is displaced in the direction shown by arrow 5, and comes to position 1a shown by dotted lines 11a, 12a, and 1'3a, respectively, at a time of (1/4) rotation Mr& from the time of zero vibration displacement.

The drawback of the conventional E-type resonator is that even if the bent crystal ophthalmoscope is used in all cut directions, which exhibit good frequency characteristics near room temperature, its resonant frequency 1-stroke temperature coefficient is It becomes a negative value, and it is difficult to set it to zero or a positive value.

The purpose of the present invention is to provide a cutting direction and position that eliminates the charge of the conventional E-type vibrator and improves the resonant frequency temperature characteristics.In order to achieve this purpose, The present invention provides E-type vibration in a state (two-cut state) in which the width direction and length direction of the vibration technique of the E-type vibrator coincide with the X-axis (electrical axis) and Y-axis (mechanical axis) of the crystal, respectively. When rotating the child around the X axis by an angle ψ (the sign of ψ is positive in the counterclockwise direction), ψ is set to an angle in the range of -25° to +35°. .

Embodiments of the present invention will be described in detail below while comparing them with conventional examples.

The resonant frequency temperature characteristic of a general V crystal resonator can be expressed as follows.

Δf = f - f.

Here, f: Resonance frequency i - T: Temperature □ fo Resonance frequency at two reference temperatures T0: Reference temperature α: Primary hot water temperature number β: Secondary temperature number r: 3 Water temperature coefficients α, β, ° r is generally determined by the cutting direction and dimensions of the vibrator.

FIG. 3 is an explanatory diagram of the dimensional parameters of the E-type vibrator according to the prior art and the present invention, where the third figure is a plan view and FIG. 3(B) is a side view. Or the length dimension of the vibrator 11, 12, 13 is shown. h indicates the width dimension e of vibration technique 11.13, ) io indicates the middle dimension of vibration technique 12. 4 indicates the length dimension of the base.

g indicates the width of the slit. t indicates the plate thickness of the vibrator.

FIG. 4 is an explanatory diagram of the cutting direction of the conventional E-type machine element. In Fig. 4, the E-type stirrer 41 is in a state where the principal direction and branch width direction of the vibration technique 42' correspond to the Y@ (machine S) and two axes (light@) of the crystal, respectively (X-cut state) Starting from , it is rotated around the X axis by an angle θ (the sign of θ is positive in the counterclockwise direction). The cut angle θ of the conventional E-type armature was selected from angles in the range of 0° to 10° at room temperature. In these angular ranges, the resonant frequency temperature characteristics of the bent crystal resonator are generally relatively good.

Figure 5 shows the water temperature coefficient α and cut-off of the conventional E-type resonator.
It is a graph showing an experimentally obtained relationship of angle θ.

Table 1 The values of the dimensional parameters of the vibrator at this time are shown in Table 1 and Table 2.
Shown in line 1. In Table 1, horizontal lines indicate that the parameters in that section are variable. Also, the reference temperature T. is 25°C. All below are T. The temperature shall be 225℃. As is clear from FIG. 5, in the conventional E-type mover, no matter how the cut angle θ was selected, the primary temperature coefficient did not become zero or positive. This tendency is the same even when the dimensional parameters have other values. FIG. 6 is an explanatory diagram of the cutting direction of the E-type vibrator of the present invention. In FIG. 6, the E-type oscillator 61 changes from a state (two-cut state) in which the branch width direction and principal direction of the vibration technique 62 coincide with the X-axis (electrical axis) and Y-axis (mechanical @) of the crystal, respectively. Starting from the beginning, it is rotated by an angle ψ (the sign of ψ is iE in the counterclockwise direction) about the X-axis.

7 to 12 are graphs showing calculated values of the temperature coefficient or temperature characteristics of the E-type vibrator of the present invention using the three-dimensional finite element method. The cut angles or dimension parameters that are kept constant during calculation are shown in Table 1, lines 3 to 8. Note that the calculated value ignores the thin film electrode over the entire area of the crystal resonator, the support member, the piezoelectricity of the crystal, etc. FIG. 7 is a graph showing how the water temperature coefficient α of the E-type vibrator of the present invention changes depending on the cut angle ψ. As is clear from Figure 7, the water temperature coefficient α shows a zero or positive value between -9'' and 26°. Originally, the cut angle at which the water temperature coefficient becomes zero is the cut angle at which the temperature characteristics are the best. However, the temperature coefficient of 1 water of a bent crystal resonator is generally equal to 1 gram of gold fixed on the surface of the crystal?
1INX tends to be pulled apart in the negative direction due to the influence of the electrode and support member. Therefore, in the present invention, the cut angle at which the water temperature coefficient α takes a positive value is also determined to be the cut angle at which the temperature characteristics are good. Figure 8 shows the width of the vibration technique with the water temperature coefficient α in the middle. This is a graph showing how it changes depending on the situation. The horizontal axis is dimensionless with the plate thickness dimension t.

By increasing the width of the middle branch from Figure 8 to 1
It can be seen that the water temperature coefficient α can be set to zero or a positive value.

FIG. 9 is a graph showing how the water temperature coefficient α changes depending on the slit width g. It can be seen from FIG. 9 that by increasing the slit width dimension, the water temperature coefficient α can be set to zero or a positive value. FIG. 10 is a graph showing how the water temperature coefficient α changes depending on the length tv of the vibration technique Qζ. Figure 10 shows that by reducing the height of Toru 1 and the height of the branch, 1
Close to the direction of the next Y-crystal coefficient αl-1 zero, Tsugukoyoshi can be seen. From the above graphs, it can be seen that the water temperature coefficient α (1) of the E-type shaker/larva of the present invention varies depending on not only the cutting angle but also the dimensional parameters, as shown in Figure 11. IBI(C) is 1 water temperature coefficient α, secondary vortex l,
It is a graph showing how the f coefficient β and the third-order temperature coefficient γ change depending on the cut angle ψ. Figure 11 (A)
Therefore, the value of the cut angle ψ at which α=0 is ψ=−14.2°. Observing the values of β and γ at this cut angle from FIG. 11(B) and FIG. 11(C), respectively, β=1.2×10−'°C−”, r=2.
2 x 10-H°C arch. Figure 12 shows the above α, β
, is a graph showing the temperature characteristics calculated from equation (1) using the values of r. From FIG. 12, the resonance wave number temperature characteristic (Δf/fo) of the E-type vibrator of the present invention is 0° to 4o' CI
! It can be seen that the J1 value is within 0.5 ppm, which is extremely good.

The E-type vibrator of the present invention is different from the conventional E-type machine Vζ.
'The reason why the resonant frequency temperature characteristics are improved can be qualitatively considered as follows. The E-type upper mover is shown in Figure 2 (
4) When photographing is carried out in the vibration mode shown in (B), there is mainly an extensional strain component in the vibrating branch part, and a shear strain component in the base part. Therefore, there are two types of elastic constants that are related to the resonance frequency, corresponding to the two types of strain components described above. The present invention is based on the fact that the temperature relationship coefficients of these elastic constants cancel each other out or are in the positive direction, whereas the conventional ones do not. 113
Figure (Shu) is a perspective view showing the electrode structure of an embodiment of the present invention.

Metal thin film electrodes 135, 136 are fixed to the side surfaces of the vibrator 131, 132, 133 made of crystal by means such as vapor deposition or sputtering. Vibration technique 131°13
A metal film 134 is fixed to the tip of 2.133 as an additional material for frequency adjustment. FIG. 13(B) is a sectional view showing the connection of the metal thin film electrodes in the back when viewed from the YY cross section of the vibration technique 131, 132, 133 in FIG. 13(4). Electrode terminals 137, 138 @ mover 130
If a voltage with a frequency equal to the resonance frequency of the fundamental vibration is applied, an alternating field of view as shown by the arrow will occur inside the vibrator 130d.
Due to the EtE effect of the crystal, the second (No (A) (B)
) Shake in the vibration mode shown in ＠-4-RO. Shizu 111 diagram is a diagram showing the seeds of electric field bunyu in one vibration technique.

Since the terminal 141 is a positive electrode and the terminal 142 is a negative electrode, there are electric lines of force 144 in the vibration technique 143. j
45 occurs, and parallel electric field components with opposite directions are generated in the upper and lower halves of the plate thickness.

FIG. 15 is a perspective view showing the support structure of the embodiment of the present invention. The electrode terminals 152 and 153;

As explained below, the present invention has the following advantages: (1) Very good resonant frequency temperature characteristics with a small and low frequency; (i) Improved wave amplitude characteristics for co-photography by utilizing the coupling of two '@ dynamic modes; Therefore, the wave number temperature characteristics are hardly affected by the dimensional error of the vibrator, the river wave number adjustment mechanism, etc.5. (4) The vibration displacement of the base part (supporting part) of the vibrator is very small over a wide range, making it extremely easy to support the vibrator. ■Since it is manufactured using photolithography technology, it has significant advantages as a high-precision, low-power resonator, including the ease of ensuring uniform characteristics and mass production. The present invention has similar effects not only in the basic imaging mode but also in the higher-order vibration mode.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the shape of an E-type vibrator according to the prior art and the present invention. Figure 2 (A) and (B) are explanatory diagrams of the vibration mode of the E-type fetus used in the conventional and the present invention. Cross-sectional view. Figure 2 (B) is a cross-sectional view of the vibration mode seen from the XX cross-section in Figure 1. Figure 3 is an explanatory diagram of the dimensional parameters of the E-type vibrator according to the conventional and the present invention. A plan view, and Fig. 3 (B) is a side view. Fig. 4 is an explanatory diagram of the cutting direction of the conventional E-type vibrator. Fig. 5 is the water temperature variation coefficient α and cut angle θ of the conventional E-type vibrator. Graph showing the relationship between. Figure 6 is an explanatory diagram of the cutting direction of the E-type vibrator of the present invention. Figure 7 is the relationship between the primary Y quality control α and the cut angle ψ of the E-type vibrator of the present invention. Fig. 8 is a graph showing the relationship between the primary function coefficient α of the E-type vibrator of the present invention and the width dimension ratio (ho/t) of the vibration technique in the middle. A graph showing the relationship between the water temperature coefficient α and the slit width dimension ratio (g/l) of the E type vibrator. Figure 10 shows the relationship between the water temperature coefficient α and the vibration technique of the E type @ face of the present invention. A graph showing the relationship between the length dimension ratio (t/l). Figures 11 (A), (B), and (C) show the 1st order 79m degree coefficient α, 2nd water temperature coefficient β, 3 of the E-type vibrator of the present invention. A graph showing the relationship between the temperature coefficient γ and the cut angle ψ.
A graph that shows how many times the Siri is running at the same time. FIG. 13(A) is a perspective view showing the electrode structure of the embodiment of the present invention. Fig. 13 (B) Fig. 13 (Cross-sectional view showing the connection of four metal electrodes from the YY cross section of Shu. Fig. 14 is a cross-sectional view to explain the electric field distribution in the vibration technique. Fig. 15) The figure is a perspective view showing the support structure of the embodiment of the present invention. E-type vibrator 61... E-type vibrator of the present invention 135.136... Metal thin film electrode 137.13
8...Electrode terminal 130.151...E type part mover 154 of the embodiment of the present invention...Airtight terminal 155.156...Stem 157... ...Conductive adhesive.

Claims (1)

[Claims] r, g (1) In a crystal resonator (E-type resonator) in which three vibration techniques are formed in an E shape on a crystal plate with a uniform valve plate thickness, the width of the vibration techniques is The direction and length direction are respectively the X@(electrical axis) of the ice crystal.
and the state that matches the Y-axis (mechanical axis) (2-cut state)
When rotating an E-type vibrator around the X axis by an angle ψ (the sign of ψ is positive in the counterclockwise direction), set the angle ψ in the range of -25° to +35°. crystal camera. (2) The crystal resonator according to claim 1, wherein electrode metal films having mutually different electrical polarities are provided on the same side of the vibrator.