JPS5928714A - Crystal oscillator - Google Patents

Abstract

PURPOSE:To miniaturize the oscillator, by tilting a cut-face of a side end of the oscillator in the axial direction at a prescribed angle in the direction of Y of the crystal axis from the normal of the major surface, keeping the temperature of inflection point of the frequency characteristic almost to room temperatrue, and decreasing the frequency change due to the ambient temperature. CONSTITUTION:The X axis of a crystal chip is taken as the lengthwise direction, a normal in parallel with a Y' axis rotated by theta in the direction of the Z axis from the Y axis is set and parallel major planes 13, 15 are formed so as to be vertical to the X axis. The direction of the normal to the major planes 13, 15 is taken as the Y' axis, an axis rotated from the Z axis by angle theta is taken as the Z' axis to form the crystal oscillator 11. Side end faces 17, 19 in the broadwise direction of the oscillator 11 are formed on a plane tilted by angle alpha closewise from the Y' axis to obtain the thickness slip crystal oscillator. Further, the 1st angle theta is taken as 34 deg.13'-35 deg.18', the 2nd angle alpha is taken as the vicinity of 5 deg., and the temperature inflection point of the frequency characteristic is taken as nearly room temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crystal resonator that performs resonant operation by thickness shear vibration, and is particularly directed to a crystal resonator with improved frequency rhA characteristics.

As an example of a conventionally known crystal resonator with thickness slip,
The longitudinal direction is the Y axis (electrical axis) of the crystal blank, and it is perpendicular to the X axis and ZlkIl (
Two main surfaces are formed that are normal or parallel to the axis that is tilted back and forth by 35 degrees in the direction of the optical axis, and the side end surfaces in the width direction of the vibrator are aligned in the direction of the two axes from the normal to the main surfaces. There was one that was tilted slightly. As for kneading, the change in resonance frequency was small even when the chest temperature became poor. At the same time, the frequency-temperature characteristic shows a substantially cubic curve, and its inflection point is at room temperature (25° C.).

However, since the above-mentioned crystal oscillator utilizes shore vibration whose frequency is inversely proportional to the stiffness of the oscillator, each dimension of the shape must be adjusted to have a frequency of 4 MHz or less. When I selected it and tried it out, the frequency-temperature characteristics were extremely unsatisfactory. For example, it has an inflection point at room temperature, and the frequency t° at that point is 3.6.
In a crystal resonator of MfJ z, the frequency change 1 ratio △ (/1
+200 ppHl at low temperature (-10°C), and +200 ppHl at high temperature (7
(0°C), it showed -300 ppm (see Figure 5). The reason for this is thought to be that unnecessary vibrations such as contour vibrations appear due to the increased pressure of the vibrator.

In this way, the known thickness-shear crystal oscillator operates at a room temperature of 25°C.
The disadvantage was that the frequency changes significantly when the ambient temperature changes.

The purpose of the present invention was to eliminate a series of drawbacks, and the inflection point temperature of the frequency-temperature characteristic was changed to approximately room temperature (:
The object of the present invention is to provide a small-sized crystal resonator whose frequency changes less even if the ambient temperature changes significantly compared to the reference frequency at the temperature.

Such an objective can be achieved in the above-mentioned crystal resonator by making the side end faces in the width direction of the resonator into cut surfaces inclined from the normal to the main surface in the Y-axis direction. Ru.

The present invention will be explained in detail below using the drawings.

Figure 1 (Δ) and concave (4) show an embodiment of the present invention.

The crystal oscillator 11 of this embodiment, like the above-mentioned known crystal oscillator, has the Y-axis of the quartz piece as the longitudinal direction, and Z&I from the Y-axis.
Rotation Y @i (Y' axis) rotated by θ in the direction of l
Two main surfaces 13.15 are formed so as to have normal lines parallel to and perpendicular to the Y axis. Here,
The normal direction to this main surface 13,151 is Y l m
+, and similarly, the axis rotated by an angle U by zlillI is set as the 2' axis.

In the width direction (Z
' axis) forms a side end surface 17.19. In this way, the Atsushi-shear crystal oscillator of the present invention is tilted by an angle α in the Y-axis direction from the direction of the normal force to its main surface, so that the side end faces in the width direction (Z' axis) are The end face was cut in an angular direction inclined in biaxial directions from the normal direction to the main surface, that is, in the counterclockwise 81 direction in the figure (opposite force direction to the present invention).

FIG. 2 shows the frequency-temperature characteristics of the crystal oscillator [Example] cut as described above, where the horizontal axis represents the temperature °r (QC) at which the crystal resonator operates, and the vertical axis represents the temperature °r (QC) at which the crystal resonator operates. What is the standard at the inflection point temperature = 25℃?
The ratio Δf'/f (ppm) of the frequency change Δf due to temperature increase to the resonant frequency t is taken. Oh, this result is the length e of the crystal resonator, the thickness L, and the side ratio e/L = 14.24, lllft+
W ToM side ratio w/l = 3.10, a = 5°
, f-36MIJz and actual h+c.

As can be seen from this characteristic, -10℃ ('1'<79
Δt'/f is within ±5 ppHl over the entire range, and the liquefaction ratio is suppressed to about 1/40 compared to the conventional one shown in FIG. Figure 5 shows
For comparison, the inclination angle of the cut direction in the width direction of the crystal resonator is zIk from the normal to the soil surface.
l.

Direction: 5°, otherwise the same as in Figure 3.

In addition, this characteristic curve is a substantially cubic function curve over the temperature range of the water oscillator, for example -106C<'1'<7 (1°), and is centered around 25°C. Change ratio Δ
t'/f is approximately symmetrical between negative and positive.

FIG. 3 shows a crystal resonator according to an embodiment of the present invention, where the width W and the original thickness ratio w/L are constant (=3.10) I, and the length l and thickness t. The frequency was measured by varying the side ratio g/L to obtain the waist frequency temperature characteristics. here,
l/L or 1422.14.23.14.24,14.2
5, the characteristics are shown by curves 31, 32, and 33, respectively.
．． 34. Note that this result is α=5°, 1'=3.6
Based on MHz, 1j=35°03'~02'.

As you can see from now on, the ambient temperature is '1' or -10°C.
Even at a temperature of 70° C., the frequency expressed in the crystal resonator of the embodiment of the present invention is mostly below 10 ppm. Therefore, the conventionally known example is '1' = 70
0te Δi'/l is approximately 300 pprn T=Niatuta Dl Compared to that, Δf/l is approximately /30, and it can be seen that the frequency-temperature characteristics are extremely good.

FIG. 4 shows a crystal resonator according to an embodiment of the present invention, in which the length l and the side ratio of the bottom of the bank are set to a constant value 1/l (=14.23), and the width W and the side ratio of the bottom of the bottom w The frequency-temperature characteristics are taken for various values of /l. Here, w/lwo 3.08.
3.09.3.10, 3.11.3, and 12 are shown by curves 41.42.43.44.45, respectively. Furthermore, this result shows that a=5°, f=3.6MkJ
z, 1J=35°03'-02'.

From FIGS. 3 and 4, the factor of the side ratio in the temperature characteristics of the crystal resonator using the cutoff method of the present invention is w/L.
) It turned out that there was someone in charge of N at e/L.

In other words, it seems that there is a strong secondary vibration in the @W direction with respect to the length β direction. Therefore, by selecting the length e and width W according to the cutting method of the present invention, it is possible to obtain a crystal resonator that is easy to manufacture and exhibits good temperature characteristics within a range suitable for large-scale production.

As described above for the embodiments, the cut surfaces of the side ends in the width direction of the vibrator are inclined at an angle a from the normal to the main surface to the Y-axis direction of the crystal axis, so that the frequency that becomes the reference frequency is particularly high. The frequency-temperature characteristics become extremely good below 4 MIJz. At the same time, the characteristics become a cubic curve, the inflection point of which can be maintained at a constant temperature, and the ratio Δf/f of the inflection point becomes symmetrical in positive and negative directions, which is extremely convenient for use.

Note that although the excitation means for the crystal resonator is not shown, there are various known means such as, for example, providing a pair of *poles on each of the two main surfaces and applying an electric field.

Furthermore, bevel processing or convex processing may be applied to suppress unnecessary vibrations and to facilitate the holding of the vibrator.

[Brief explanation of the drawing]

Figure 1 (Al and (B+) are front and perspective views showing one embodiment of the crystal resonator according to the present invention, Figure 2 11j Characteristic diagram showing the change ratio of temperature versus oscillation frequency in one embodiment of the present invention , FIG. 3 is a diagram showing the characteristics of the change ratio of temperature versus oscillation frequency when the side ratio w/l is kept constant in the embodiment of the present invention and the ratio 1/L between length and width is changed. 4
The figure is a diagram showing the characteristics of the change ratio of the oscillation frequency versus temperature when the length-to-thickness ratio e/L is kept constant and the side ratio w/L is changed in the embodiment of the present invention. FIG. 2 is a diagram showing the temperature characteristics of a conventionally known crystal resonator. 11...Crystal resonator, 13.15...-main surface, 17.
19.- side end surface, 31-34. 41-45. Characteristic curve. Patent applicant: Kyoto Ceramic Co., Ltd.

Claims (1)

[Claims] 1. The longitudinal direction is taken on the Y axis of the Mizushima piece, and 1 on the two axes from the Y axis.
The main surface has a normal parallel to the rotational Y-axis rotated by 181 angle 0 and is perpendicular to the Y-axis, and the side end surface in the width direction is parallel to the Y-axis from the normal. A crystal resonator characterized in that it is formed of surfaces inclined by two angles α. 2. In the crystal resonator according to claim 1,
A crystal resonator characterized in that the j61 angle θ is formed by a circle ranging from 34°13' to 35'18'. 3. In the crystal resonator according to claim 1,
A crystal resonator characterized in that the second angle α is around 5°. 4. The crystal resonator according to any one of claims 1 to 3, characterized in that the temperature characteristic of the ratio of the frequency change lid due to temperature to the resonance frequency is a bending point temperature or approximately room temperature. crystal oscillator. 5. In the crystal resonator according to claim 4,
A crystal resonator characterized in that the inflection point temperature is 4 MHz or higher.