JPH03192911A - Short-side crystal resonator - Google Patents

Abstract

PURPOSE:To attain miniaturization, to enhance impact resistance and to decrease an equivalent series resistance by providing a step difference to a vibration part, providing an exciting electrode of IDT shape and integrating the vibration part, a support part, a frame and a mount part with the etching method. CONSTITUTION:A vibrator 1 consists of a vibration part 2, a support 3, a frame 4 and a mount part 5 and they are integrated by the etching method. Moreover, the thickness in the direction of a long side of the vibration part 2 is not uniform but has a step difference and exciting electrodes 7, 8 of the interdigital electrode (IDT) shape are provided to both upper and lower faces of the vibration part 2 and given the same polarity as upper and lower opposite electrodes. Thus, the small size short-side crystal resonator with excellent impact resistance and small equivalent series resistance is obtained.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to the shape and excitation electrode arrangement method of a short-side crystal resonator in which a vibrating part, a support part, and a frame are integrally formed by an etching method. IC with strong demand for thin and small size
This invention relates to a short-side crystal oscillator that is optimal as a reference signal source for mobile devices such as cards and pagers.

[Summary of the Invention] The purpose of the present invention is to provide a short-side crystal resonator with very small vibration leakage, low equivalent series resistance R+, and a high Q value. The vibrating part and the supporting part are integrally formed by etching through the bridge part, a frame connected from one end of the supporting part is formed to surround the vibrating part and the supporting part, and the mount part and It is connected. In addition, the thickness of the vibrating part in the long side direction is not uniform, and a step is provided, and excitation electrodes in the shape of interdigitated electrodes (hereinafter referred to as IDT) are provided on both the upper and lower surfaces of the vibrating part, and the upper and lower opposing electrodes are the same. It is a short-sided crystal resonator that is formed to serve as a pole. By forming the vibrator in this manner, the object of the present invention is achieved.

[Conventional Techniques] As shown in Japanese Patent Application Laid-Open No. 53-132988 and Japanese Patent Application No. 53-160737, a conventional short-side crystal oscillator has a vibrating part and a supporting part integrally formed by an etching method, and its mount. The conventional method was to support and fix the support part to a support pedestal or the like at both ends. Furthermore, one excitation electrode was disposed on the entire upper and lower surfaces of the vibrating section, and the thickness of the vibrating section was uniform.

(Problems to be Solved by the Invention) As mentioned above, in the conventional short-side crystal resonator, the mount parts are provided at both ends of the vibrating part. This was difficult and caused high costs. At the same time, it had the problem of being weak against shock. In addition, since the excitation electrodes are placed on the top and bottom surfaces of the vibrating section, a Z-plate vibrator cannot be piezoelectrically excited, resulting in poor piezoelectric efficiency and the need to form the vibrator with a cut angle that is unprofitable. I didn't get it. For this reason, there remained a major drawback, such as the inability to obtain inexpensive vibrators.

[Means for Solving the Problems 1] The present invention solves the above problems by the following method. In other words, it is a short-side crystal resonator consisting of a vibrating part and a support part that are largely displaced in the short-side direction, and the support part is a bridge part,
The frame is composed of a damping part and a mount part, and the frame connected to the mount part is formed so as to surround the vibrating part, and the thickness of the vibrating part in the long side direction is not uniform and forms a step. The object of the present invention is achieved by the configuration.

[Function] As described above, the short side crystal resonator of the present invention has a vibrating part, a supporting part,
It consists of a frame and a mount part, and the thickness of the vibrating part is not uniform and there are steps. As a result, it is possible to obtain an inexpensive short-side crystal resonator that is small in size, has excellent impact resistance, has a low uniform series resistance R3, and has a high Q value.

[Example J Next, the present invention will be specifically described based on an example. 1st
The figure is a plan view of a -★ example of the short-side crystal resonator shape and excitation electrode arrangement of the present invention, and the cross-sectional view of the AA' section showing the electrodes in the long side direction of the vibrating part 2 in the same figure is the second one. It is a diagram. The vibrator 1 is composed of a vibrating part 2, a support part 3, a frame 4, and a mount part 5, which are integrally formed by etching.

Further, in the long side direction, excitation electrodes having different polarities are alternately arranged on the upper and lower surfaces of the vibrating section 2, which has an uneven thickness and a step. This is called an IDT shaped electrode, i.e.
A plurality of excitation electrodes 7.8 are formed and extended to the mount portion 5. The plan view in Figure 1 shows only one side, but as shown in the cross-sectional view in Figure 2, the steps are used to ensure that both sides face each other in the long side direction and are symmetrical in the thickness direction. With this arrangement, the object of the present invention can be achieved.

Also, the excitation electrode 7. is connected through the electrode terminal a + * b +.
Vibration can be caused in the short side direction by applying alternating voltage between 6 is provided, and as the short side vibrates, the support part 3 is also displaced in the direction perpendicular to it, so this displacement is converted into a bending mode, and the support part 3 is connected to the frame 4, and the mount part 5 Supported and fixed. Therefore, a short-side crystal resonator with a high Q value and a small equivalent series resistance R1 without vibration leakage can be obtained. In addition, since the vibrator of the present invention can be integrally formed from the Z plate with the vibrating part, support part, frame and mount part by etching, it is possible to reduce the cost of the vibrator, reduce its size, and have excellent shock resistance. A short side crystal resonator is obtained.

[Effects of the Invention] As described above, the present invention has a vibrating section with a stepped shape, an IDT-shaped excitation electrode, and etching the vibrating section, support section, frame, and mount section. By proposing a new shaped short-side crystal oscillator that is integrally formed, the following remarkable effects can be achieved.

■ By devising and improving the shape of the support part and frame, vibration can be made free, so the constant series resistance R3 becomes small.

(2) By providing a step in the thickness of the vibrating part and making the excitation electrode into an IDT shape, it is possible to use a Z plate as a short-side crystal resonator, which can be made inexpensive. At the same time, the piezoelectric efficiency improves, so 1
The equivalent tooth row resistance R1 becomes smaller.

■The vibrating part, support part, frame and mount part are integrally molded using the etching method, allowing for miniaturization.

■At the same time, it has excellent impact resistance.

- Since the support part is connected to the frame, vibration leakage is small (and the series resistance R1 is small.

■Since it is supported and fixed to a pedestal, lead wire, etc. with a mount that does not affect vibration, vibration leakage is reduced.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the short-side crystal resonator shape and excitation electrode arrangement of the present invention. FIG. 2 is a sectional view showing the electrode structure of section A--A in FIG. 1. l... Vibrator... Vibration part... Support part... Frame... Mount part... Hole... Excitation electrode... Bridge part b' - Electrode terminal

Claims (1)

[Claims] This is a short-side crystal resonator consisting of a vibrating part that is largely displaced in the direction of the short side, and a support part.The support part is made up of a bridge part, a damping part, and a mount part, and a frame connected to the mount part surrounds the vibrating part. 1. A short-side crystal resonator characterized in that the thickness of the vibrating part in the long side direction is not uniform and is stepped.