JPS5854717A - Crystal oscillator - Google Patents

Abstract

PURPOSE:To improve the mass-productivity, to attain excellent characteristics and to attain ease of support, by arranging a surface electrode for its free end so as to perform bending oscillation almost vertically to the plate surface, and gradually reducing the amplitude of oscillation toward the fixed part. CONSTITUTION:Excitation electrodes 2, 3 are arranged to provide an electric field required for the oscillation for the upper end of a crystal oscillator plate 1 in the bending mode mainly to the vicinity of the end. A part of the electrodes 2, 3 is prolonged as a lead pattern to the lower end of the plate 1 and directly bonded to leads 4, 5 of a hermetic terminal 6 with solder. The bending oscillation is maximum for the amplitude at the upper end of the plate, and gradually reduced to lower side and the amplitude is reduced to zero at the lower end. The osillation mode at an arbitrary height of the plate 1 is almost similar, and since the bending oscillation of a rod having free both ends is balanced by itself, the plate 1 performs oscillation without leakage of oscillation externally with well balance as a whole, in spite of its the simple shape.

Description

[Detailed description of the invention] This invention relates to a zero quartz crystal resonator with a new vibration mode.

Conventionally, tuning fork type or lens type AT plates have been used as crystal resonators that are ultra-compact, have relatively flat frequency-temperature characteristics, and are easy to manufacture, and have been mainly used in quartz crystal resonators. However, in the tuning fork type, the oscillation frequency is a little too low, so fine adjustment of the output frequency using a frequency divider with a variable division ratio becomes too rough, which is inconvenient, and the natural frequencies of the left and right branches of the tuning fork do not match. Even if the degree of deviation slightly deviates due to a manufacturing error, characteristics tend to deteriorate, and even in mass production, this is a factor in lowering yields. On the other hand, the frequency-temperature characteristics of AT plate resonators are difficult to compensate for. Furthermore, since the lenses are processed one at a time, it is not possible to simultaneously process a large number of vibrating elements within a crystal block or wafer, which inevitably increases costs.

In the present invention, we have created a vibrator that eliminates the drawbacks of these conventional products and has the advantages. It was made for the purpose of 4J filters, and has excellent mass productivity, is easy to support, does not require special consideration of shape balance, and has relatively excellent temperature characteristics.
Since the oscillator that can wait for II and has a moderately high frequency is '14+A), J')6. This will be explained based on the J-So and F drawings.

FIG. 1 is a perspective view showing the structure of a vibrator including support inside a container according to an embodiment of the present invention.

1 is a plate-shaped crystal oscillator, 2 and 6 are excitation electrodes, and the upper end of plate 1 is connected to a bending moat (the end face is perpendicular to the plate surface), which is shown by an imaginary line on one side of the figure. It is arranged so that the electric field necessary for vibrating (deformation similar to vibration) is mainly applied to the vicinity of the end.

A part of the electrode film 2, O, is extended as a reed pattern to the lower end of the plate 1, and the lead wires 4 and 5 of the hermetic terminal O are
It is directly connected by means such as...

That is, the lower end of the plate 1 should be fixed to the container. Therefore, the bending vibration reaches its maximum swing rlJ at the top end of the board, gradually decreases downward, and reaches zero swing rIJ at the top end of the board. The vibration behavior of plate 1 at any given height is almost similar, and the bending vibration of the rod, which is free at both ends, is balanced by itself (there is no reaction to the support system), so plate 1 has a simple shape. Despite this, the overall vibration is well-balanced and there is no vibration leakage to the outside. Although there is a tendency to vibrate the lower end of the plate, the effect of fixing the lower end and the effective excitation part of the electrode film being at the upper end results in vibration with a sufficiently high Q.

Furthermore, since both this embodiment and the conventional tuning fork have a common point of bending vibration, the end surface of the plate is the plate surface from which the tuning fork is cut out (so-called +5
At °Z cut I, as shown in Figure 2, consistent with 1),
If the direction of the crystal is as shown in Figure 2 (11) and the orientation is as shown in Figure 2, you can expect a temperature characteristic at least equivalent to that of a tuning fork.Also, by shaking the vibration mode 1, the cantilever force 1 (
It is easier to obtain a considerably higher frequency than -1) of the song.

An example of changing the shape of the diaphragm in order to further increase the effect of confining vibration energy to the end of the plate is shown in FIG. 3 along with other embodiments.

Figure 3 (a) shows the middle part of the board is narrowed down, and No. 31m (b) is a hole made to leave the real part only in the part corresponding to the node of the free rod at both ends, which has a length equal to the length of the board [1]. [Example of changing the cross section to increase the insulation effect of the fixed end/＼ in the direction of -4, Fig. 3(C) shows the thinning toward the fixed end, and Fig. 3(d) shows the thickening of the tip. This is an example of making it difficult to vibrate the base by changing the natural frequencies of bending of the base and other parts. These shapes can be directly etched from a quartz wafer and lino-cut in large numbers at the same time, like a fork, or by cutting into a quartz block in a lattice pattern with a wire or blade saw, a rectangular parallelepiped as shown in Figure 1 can be created. It would also be possible to obtain a large number of crystal pieces, align them, grind the sides, and mold them. Although not shown in the drawings, the thickness of the plate may be varied by notching or grinding midway along the plate surface from the free end to the fixed end. Furthermore, instead of flattening the edges of the plate, it is also possible to make them somewhat convex or concave.

As is clear from the above description, in the present invention, the vibrator is constructed by cantilever-supporting a plate-shaped vibrator that is simple and has a well-balanced shape. This has the effect of providing a vibrator that is easy to support, inexpensive, has a moderately high frequency, and has excellent characteristics.

Of course, the cutting angle and the shape of the plate material are not limited to those shown in the drawings.

[Brief explanation of drawings]

Fig. 1 is a perspective view of one embodiment of the present invention, Fig. 2 is an explanatory diagram showing an example of the cutting direction of a crystal plate, and each figure in Fig. 3 is a plane of the outline of a crystal plate in other embodiments. It is a diagram. 1...Crystal plate, 2.6...Excitation electrode.

Claims (1)

[Claims] One end of a plate made of quartz material is fixed, a surface electrode is arranged so that the free end of the plate makes bending vibration in a direction almost perpendicular to the plate surface, and as the vibration 1] approaches the fixed end, A crystal oscillator characterized in that it is configured to reduce the number of crystals to 5.