JPH04255105A - Thickness-shear crystal vibrator - Google Patents

Abstract

PURPOSE:To improve the yield, to reduce the cost through mass-production and to make the size small by providing a weight for frequency adjustment to almost the entire face of an exciting electrode placed on both sides of a vibration part so as to increase the frequency adjustment quantity thereby obtaining a prescribed resonance frequency even with rough thickness accuracy. CONSTITUTION:An exciting electrode 2 is provided to both sides of a vibration part of a crystal resonator 1 comprising a support part and the vibration part formed by the photolithography method from a crystal plate cut out from a Y plate while being turned by nearly 35 deg. around an X axis as a turning axis. A frequency adjustment weight 3 is vapor-deposited to almost the entire face of the electrode 2 through a hole 4a made to a seat base 4 of almost the same shape as the electrode 2 and a mask having an opening of the entirely same shape as the hole 4a. In this case the vibrator 1 and the seat base 4 are fixed and connected electrically with a conductive adhesives 5 and the frequency is adjusted by adjusting the weight from both the sides. Thus, the frequency adjustment quantity is increased, a prescribed resonance frequency is obtained even with rough thickness accuracy, the yield is improved, the cost is reduced and the size is made small.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a small thickness sliding crystal oscillator used in various communication devices that have advanced to higher frequencies and mobile devices such as IC cards that are expected to be used in the future.
In particular, it relates to ensuring a frequency adjustment range.

0002

2. Description of the Related Art FIG. 5 is a front view of a conventional disc type AT-cut crystal resonator. In FIG. 5, 1 is a crystal resonator, 6 is an electrode terminal with a slit for supporting the crystal resonator, and 2 is an excitation electrode placed approximately in the center of the crystal resonator. 3 is a weight 3 of a secondary pattern for frequency adjustment, which is formed by vapor deposition. In order to miniaturize the conventional AT-cut crystal resonator as shown in FIG. 5, it is necessary to sufficiently reduce its diameter, but reducing the diameter leads to deterioration of characteristics, making it difficult to miniaturize. In addition, although it was not small, the vibrator had a large amount of energy, and a frequency adjustment amount of several thousand (ppm) could be secured with the weight 3 having a secondary adjustment pattern on only one side.

FIG. 6 is a perspective view of a rectangular AT-cut crystal resonator that is further miniaturized because the disk shape described above is too large. The length x0 is selected in the direction of the electric axis X-axis of the crystal, that is, the vibrator has the largest dimension in the X-axis direction. Further, the directions of the thickness y0 and the width z0 coincide with the directions of new axes Y' and Z' formed by the mechanical axis Y and the optical axis Z, respectively, when rotated about the X axis. The direction of displacement of this vibration is parallel to the X-axis, so if it is supported at the end of the crystal in the X-axis direction, there is a drawback that there is a lot of energy loss, leading to deterioration of characteristics.Especially regarding the length x0 for miniaturization. noticeable. In addition, even with a rectangular AT-cut crystal resonator that has a smaller disc shape, it is possible to achieve a frequency adjustment of several thousand (ppm) on one side.
It was possible to secure the same amount of frequency adjustment.

0004

[Problems to be Solved by the Invention] In view of the recent trends in market demands, the above-mentioned disk-shaped and rectangular AT-cut crystal resonators have a high frequency and are miniaturized to be suitable for surface mounting. In this case, making the crystal resonator smaller has the following disadvantages. In other words, as the area of the vibrating part becomes smaller, the energy held by the vibrator becomes smaller.
If a weight is added when adjusting the resonant frequency, the loss of energy due to the weight will be large and the amount of frequency adjustment will be reduced, increasing the number of items that cannot be frequency adjusted, resulting in a decrease in yield.

The present invention is a thickness shear resonator, which is determined only by the thickness y0 of the plate, and the relationship between thickness and frequency becomes steeper as the frequency increases, and the accuracy of the resonance frequency can be improved by increasing the thickness accuracy. There is a limit to increasing the frequency, and the problem of the present invention is how to add a weight for frequency adjustment to increase the frequency adjustment range.

[0006]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a vibrating section formed by photolithography from a quartz plate cut out by rotating a Y plate by about 35 degrees about the X axis. A thickness shear crystal resonator comprising a support section and a support section, wherein an excitation electrode is provided in the vibrating section, and weights for frequency adjustment are provided on almost the entire surface of the excitation electrode on both sides of the vibrating section. It is a vibrator.

[0007]

[Function] Miniaturizes the shape of the thickness-slip crystal resonator,
Containing energy using a single electrode is an effective way to avoid the effects of contour vibration even if the crystal oscillator is sufficiently small relative to its thickness.This method is used to determine the shape of the crystal oscillator. Frequency adjustment is achieved by providing frequency adjustment weights on both sides of the vibrating section on almost the entire surface of the excitation electrode.

[0008]

[Example] To explain the basic technical background of the present invention, FIG. 3 shows the frequency adjustment of a crystal resonator.
It shows the frequency change and equivalent series resistance change when a weight is attached to almost the entire surface of the excitation electrode by vapor deposition. At the frequency of point A in Fig. 3, the energy confinement by a single electrode is complete and the characteristics show good values.As the frequency is changed using a single-sided evaporation weight, the characteristics deteriorate as shown by the broken line, but both sides If the weights are deposited evenly, they will deteriorate at a slope of about 1/2 on one side, as shown by the solid line. Therefore, since the slope of deterioration is smaller than in single-sided adjustment, the amount of frequency adjustment increases.

FIG. 4 shows the amount of frequency adjustment for adjusting to a predetermined resonance frequency with respect to variations in plate thickness. According to the present invention, the amount of frequency adjustment is increased, specifications are made loose with respect to thickness variations, and manufacturing is simplified. A concrete implementation example will be described below based on the above background. FIGS. 1A and 1B are a plan view and a side view of a crystal resonator of the present invention. 1 is a crystal oscillator, 2 is an excitation electrode placed almost in the center of the crystal oscillator 1, and is also placed symmetrically on the back side; 3 is a weight for frequency adjustment on almost the entire surface of the excitation electrode 2; , which are provided on both sides of the vibrating section.

FIGS. 2A and 2B are a plan view and a side view of the crystal resonator 1 of the present invention mounted on a pedestal. 1 is a crystal oscillator, 2 is an excitation electrode 2 placed almost in the center of the crystal oscillator 1, and is also symmetrically placed on the back side, 3 is a weight 3 for frequency adjustment on almost the entire surface of the excitation electrode 2. are provided on both sides of the vibrating part. 4 is a pedestal for supporting the crystal oscillator and is made of ceramic or the like. 5 is the crystal oscillator 1.
This is a conductive adhesive for fixing and electrically connecting the base 4 and the base 4. A hole 4a is made in the center of the pedestal 4, and its shape is almost the same as that of the excitation electrode.
The weight 3 is deposited through this hole 4a. On the other side, a mask (not shown) having an opening having the same shape as the hole 4a of the pedestal 4 is erected, and the weight 3 is deposited through this mask, thereby adjusting the frequency from both sides of the vibrating part. I do,
This adjustment may be performed on both sides at the same time, or may be repeated from one side as necessary.

[0011]

Effects of the Invention As described above, in the thickness-shear crystal oscillator according to the present invention, the effect of reducing the amount of frequency adjustment when downsized can be reduced by using a weight for frequency adjustment on almost the entire surface of the excitation electrode. By providing on both sides of the vibrating part,
The amount of frequency adjustment can be increased and the thickness accuracy can be made looser, allowing the specified resonant frequency to be obtained without tightening the thickness accuracy, improving yields, and making it possible to mass-produce an inexpensive and compact thickness-shear crystal resonator. It provides:

[Brief explanation of the drawing]

FIGS. 1A and 1B are a plan view (A) and a side view (B) of a crystal resonator of the present invention.

FIGS. 2A and 2B are a plan view (A) and a side view (B) of the crystal resonator of the present invention mounted on a pedestal.

FIG. 3 is a characteristic diagram showing frequency changes and equivalent series resistance changes when a weight is deposited.

FIG. 4 is a characteristic diagram showing the amount of frequency adjustment for adjusting to a predetermined resonance frequency with respect to variations in plate thickness.

FIG. 5 shows a front view of a conventional disk type thickness-shear crystal resonator.

FIG. 6 shows a perspective view of a conventional rectangular thickness-shear crystal resonator.

[Explanation of symbols]

1 Crystal resonator 2 Excitation electrode 3 Weight 4 Pedestal 5 Conductive adhesive 6 Electrode lead

Claims (1)

[Claims] Claim 1: In a thickness-shear crystal resonator consisting of a vibrating part and a supporting part formed by a photolithography method from a crystal plate cut out by rotating a Y-plate by about 35 degrees about the X-axis, vibration 1. A thickness-shear crystal resonator, characterized in that an excitation electrode is provided in the vibrating portion, and weights for frequency adjustment are provided on almost the entire surface of the excitation electrode on both sides of the vibrating portion.