JPS6355247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support structure for a thickness-shear crystal resonator.

In recent years, AT-cut thickness-slide crystal units have been attracting attention due to their excellent frequency-temperature characteristics and aging characteristics in response to the demands of high-precision wristwatches. However, in order to put this into practical use, the technical challenge is to create a support structure for the vibrator piece that can be miniaturized without increasing the effective resistance (hereinafter referred to as CI value).

For this purpose, various support structures have been proposed in the past. For example, as shown in FIG. 1, a support member 3 is fixed to two lead terminals 2 that are hermetically fixed to a base container 1, A structure is known in which both ends of the thickness-sliding crystal resonator piece 4 in the longitudinal direction are held between the support member 3 and the cap 5 is vacuum-sealed by cold pressure welding.

However, according to this structure, the process of attaching the support member 3 and the process of clamping the vibrator piece 4 to the support member 3 are extremely troublesome operations, which are not suitable for mass production.Moreover, the operations must be performed through a microscope, which requires skill. Otherwise, there is a risk that the end portion of the vibrator piece 4 may be damaged by the support member 3. There is also the additional drawback that the base container and cap are expensive due to the use of cold pressure welding as the sealing method. Furthermore, sufficient miniaturization to be adopted as a wristwatch has not been achieved, and the above technical problem has not been solved.

Furthermore, as shown in FIG. 2, a structure is known in which both ends of a vibrator piece 4 are fixed to a lead terminal 2 with solder or an adhesive 6. However, in this structure, since both ends of the vibrator piece 4 are fixed, although the impact resistance is improved, the main vibration is suppressed and the CI value increases, making it impossible to obtain the desired electrical characteristics. do not have. Furthermore, like the structure shown in FIG. 1, the desired miniaturization has not been achieved and it cannot be used as a high-precision wristwatch.

The purpose of the present invention is to eliminate the drawbacks of the conventional structure described above, to realize an ultra-compact support structure with a low CI value and excellent impact resistance, and to provide a rod-like thickness sliding structure suitable for use in high-precision wristwatches. The goal is to provide vibrators.

Another object of the present invention is that the manufacturing process is simple;
Another object of the present invention is to provide a support structure for a rod-shaped thick shear vibrator that can be mass-produced and can be encapsulated by a press-fitting method.

The present invention focuses on the fact that the main vibration is suppressed by fixing both ends in the longitudinal direction (X-axis direction) of an AT-cut thickness-sliding crystal resonator piece. We attempted to realize an ultra-small thickness-sliding crystal resonator piece by directly fixing the resonator piece to a base like a crystal resonator, and as a result of various experiments, we arrived at the present invention.

According to the present invention, a rod-shaped thickness shear vibrator piece;
a base having a recess in the center of the upper surface and a groove adjacent to the recess; one end in the longitudinal direction of the crystal resonator piece crosses the recess and is fixed in the groove; Provided is a support structure for a thickness-shear crystal resonator, characterized in that the center portion in the width direction of the fixed end of the resonator piece is released without contacting the base.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

The thickness shear crystal resonator piece used in the present invention is, for example, an AT cut thickness shear crystal piece 7 as shown in FIG. The crystal piece 7 has a beveled portion 7a at both ends in the X-axis direction, and an electrode film 8 made of gold, silver, aluminum, etc. is provided on both sides of the beveled portion 7a.
And an extraction electrode film 9 is formed by vapor deposition or sputtering.

FIG. 4 shows a base 10 that supports the crystal piece 7. A metal ring 12 is fitted around the outer periphery of an insulating base 11 made of hard glass, ceramic, insulating resin, etc., and two lead terminals 13 are connected to the base 10. It is buried in an insulating base 11 in a hermetically sealed manner. On the upper surface of the insulating base 11, a recess 14 having an appropriate shape such as a circle and an appropriate depth is formed in the center, and a cut groove 17 is formed at a position adjacent to the recess 14.
It is necessary that the depth of the recess 7 is shallower than that of the recess 14.

Further, the position of the cut groove 17 is on a straight line connecting the upper ends of the two lead terminals 13, and the upper end of the lead terminal 13 is located on the bottom surface of the cut groove 17.

FIG. 5 shows a support structure for the crystal blank 7, and shows one end of the crystal blank 7 in the longitudinal direction (X-axis direction), that is, the end where the extraction electrode film 9 extends (the left end in FIG. 3). ) is fitted into the cut groove 17 and fixed with an adhesive (not shown) such as solder or conductive adhesive. As a result, the crystal piece 7 is connected to the insulating base 11.
The central part of the fixed end of the crystal piece 7 in the width direction (Z-axis direction) is fixed directly to the base 10 by crossing the recess 14 of the crystal piece 7. Released without contact with 10. Further, each electrode 8 of the crystal piece 7 is electrically connected to the upper end of each lead terminal 13 via each lead electrode 9 using a bonding agent.

In this way, after one end of the crystal piece 7 is directly fixed to the base 10, the closed cap 16 shown by the broken line is closed.
is pushed into the outer periphery of the metal ring 12 of the base 10 and sealed. In order to seal by this press-fitting method, both the adhesive surfaces of the hermetic cap 16 and the metal ring are previously soldered or plated.

Next, in order to evaluate the performance of the vibrator having the support structure of this example, an experiment was conducted to measure the CI value. If it sticks,
Although the upper limit was 80Ω, it was found that with the support structure of this example, a good CI value of 50Ω or less could be obtained. Incidentally, in the case of the conventional structure shown in Fig. 2, the limit was 100Ω.

In the structure of the embodiment described above, the side in the width direction (Z' axis direction) of one end of the crystal piece 7 is connected to both lead terminals 1.
It is also possible to provide the cut groove 17 perpendicular to the straight line connecting the upper ends of the lead terminals 13, but in this case, the upper ends of the lead terminals 13 are slightly protruded from the upper surface of the insulating base 11, and the upper ends of the lead terminals 13 are and the extraction electrode 9 of the crystal piece 7 may be electrically connected by a thin metal wire.

As described in detail above, according to the present invention, by forming a recess in the base and fixing the crystal piece across the recess, the central part in the width direction of the fixed end of the crystal piece is connected to the base. Because they are released without contact, the CI value can be kept small and a high-performance rod-shaped thickness-shear crystal resonator can be obtained.

Further, according to the present invention, a cut groove is formed on the base,
Since the fixed end of the crystal piece is inserted into the cut groove and the crystal piece is planted, the impact resistance is extremely good, and the planting position of the crystal piece is defined by the cut groove. There is no displacement of the fixed part of the crystal piece, and a stable CI value can be obtained. Furthermore, unlike conventional structures, the space required for crystal piece supporting members such as lead terminals and support members is no longer required, making it possible to achieve ultra-miniaturization comparable to that of a tuning fork-type crystal resonator, and at the same time, it is possible to separate the base and cap from each other. This makes it possible to use the largest crystal piece for the internal volume of the holder, making it possible to apply it to high-precision wristwatches.

In addition, the manufacturing process is extremely simple compared to conventional structures, and sealing by press-fitting is also possible, and it has various advantages such as low cost and suitability for mass production, and has great industrial value. is extremely high.

Note that the present invention is not limited to the above-described embodiments; for example, a sliding crystal piece with a different thickness from the AT-cut crystal piece may be used, and various changes can be made without departing from the gist of the present invention. be.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing conventional support structures for rod-shaped thickness shear crystal resonators, FIG. 3 is a perspective view showing an example of rod-shaped thickness shear crystal resonator pieces, and FIG.
The figure is a perspective view showing an example of the base according to the invention, and FIG. 5 is a perspective view showing an example of the support structure of the invention. Reference numeral 7 indicates a bar-shaped thickness sliding crystal resonator piece, 10 a base, 14 a recess, and 17 a cut groove.

Claims (1)

[Claims] 1 Consisting of a rod-shaped thickness-sliding crystal resonator piece and a base having a recess in the center of the upper surface and a groove adjacent to the recess, one longitudinal end of the crystal resonator piece crosses the recess. 1. A support structure for a thickness-shear resonator, which is fixed in a cut groove and is configured so that the center portion in the width direction of the fixed end of the crystal resonator piece does not come into contact with a base and is released.