JPS61201512A - Piezoelectric vibrator - Google Patents

Abstract

PURPOSE:To attain high frequency application by contacting one of connecting terminals to an upper electrode and the other to a frame at the rear face of the piezoelectric vibrator chip while the vibration of a diaphragm is not hindered and sealing the entire part by a glass bulb. CONSTITUTION:A projection 12 of one connection terminal 2 is contacted to the upper electrode 7 and the projection 13 of the other terminal 3 is contacted to the frame 10 at the rear face of the piezoelectric vibrator chip 1. In this case, since a head center of the terminals 2, 3 is recessed, the diaphragm 9 exists while being suspended in a space A formed by the opposed recesses and the vibration of the diaphragm 9 is not hindered by other members. Thus, even when the diaphragm is miniaturized, the connection with the frame is formed accurately to a proper position in response to the vibrating mode and high frequency application of the piezoelectric vibrator chip is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric vibrator used for applications such as filters and two-terminal resonators.

The vibration modes of the vertical strain piezoelectric vibrator are bending vibration, length vibration,
There are many types of vibration such as spreading vibration, and among them, for example, crystal resonators and ceramic resonators are mainstream as piezoelectric vibrators having a spreading vibration mode.

This resonator has a support structure in which the central part of both sides of the resonator chip is sandwiched between support members.However, with the Okagi support structure, when the resonator chip becomes smaller, the central part of the resonator chip becomes smaller. Therefore, it is difficult to support a vibrator using a spreading vibration mode at a high frequency of MHz or higher.

In addition, the conventional mounting structures for piezoelectric vibrators have been simple resin packages or expensive hermetic seals, which have caused the following problems.

In other words, products with a simple resin package cannot be used under harsh conditions such as an active gas atmosphere and have reliability problems, while products with a hermetically sealed resin package do not have such problems. Although it is not available, it has the disadvantage of being expensive.

Therefore, none of the conventional devices has been able to achieve both reliability and price.

The problem of increasing the frequency of a piezoelectric vibrator has been explained using a vibrator using a spread vibration mode for convenience, but the problem is also common to vibrators using other vibration modes, although there are differences in frequency.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide an extremely useful piezoelectric vibrator that is capable of increasing the frequency and is both inexpensive and reliable.

In order to achieve the above object, the piezoelectric vibrator according to the present invention has a piezoelectric member formed on the surface of a metal substrate on which the diaphragm part is integrally connected to the frame part, and It consists of a piezoelectric vibrator chip having a circular outer shape forming an upper electrode, a pair of connecting terminals, and a glass bulb for sealing, and one of the connecting terminals is connected to the upper electrode without inhibiting the vibration of the diaphragm. , and the other is brought into contact with the frame portion on the back side of the pressure TGI element chip, and is sealed with a glass bulb.

Figure 1 shows a front sectional view of the entire piezoelectric vibrator, in which 1 is a piezoelectric vibrator chip, 2 and 3 are a pair of connection terminals, and 4 is a glass bulb.

The piezoelectric vibrator chip 1 is composed of a metal base +7i5, a piezoelectric member 6, and an upper electrode 7, and has a circular outer shape.

As shown in FIG. 2, the metal substrate 5 is provided with a diaphragm portion 9 in the center and a frame portion 10 on the periphery by forming two concave through holes 8, 8 facing each other. between 2
It has a structure in which it is integrally connected by a book arm 11.11.

A constant elastic material such as Elinvar material is used as the metal substrate 5, and is formed into the shape shown in the figure by etching or the like.

For example, ZnO is used as the piezoelectric member 6, and is formed over the entire surface of the metal substrate 5 by a thin film forming method such as sputtering or vapor deposition.

It is sufficient to form the piezoelectric member 6 on the entire surface of the metal substrate 5 and at least on the surface of the diaphragm portion 9, but in this embodiment, the piezoelectric member 6 is formed between the metal substrate 5 and the upper electrode 7 by utilizing the properties of the piezoelectric member as an insulator. In order to provide the necessary insulation between the diaphragms and the like, these are also formed on the frame portion 10 other than the diaphragm portion 9 and on the arms 11 and 11.

The upper electrode 7 is formed on the piezoelectric member 6 using the same formation method as that of the piezoelectric member. The electrode 7 is formed to extend from the diaphragm section 9 through the arm 11 to above the frame section 10, as shown in FIG.

For example, dimeft wires are used for the connection terminals 2 and 3.

The connection terminal 2.3 has a cylindrical shape with approximately the same diameter as the piezoelectric vibrator chip l, and its head is bored in the center to form a convex portion 12.13 on the periphery. has been done.

One connection terminal 2 is provided with its convex portion 12 in contact with the upper electrode 7, and the other connection terminal 3 is provided with its convex portion 13 in contact with the frame portion 10 on the back side of the piezoelectric vibrator chip 1. It will be done.

In this case, since the center of the head of each connection terminal 2.3 is recessed, the diaphragm portion 9 exists in a suspended state in the space A formed by the opposing recessed portions, and the diaphragm portion The vibration of 9 is not inhibited by other members.

Note that the convex portions 12, 13 can be formed by providing contact holes without boring the connecting terminals 2, 3.

In addition, in the illustrated example, the connection terminals 2.3 are lead wires 2a, 3a.
However, it is also possible to use a piezoelectric vibrator without lead wires and configure it as a chip-type piezoelectric vibrator that is directly attached to a wiring pattern on a printed board or the like.

The glass bulb 4 is constructed by sandwiching the piezoelectric vibrator chip 1 with the connecting terminals 2.3 and
It is extrapolated to the connecting terminal 2.3, melted in an inert atmosphere such as A' or N2, and sealed to the connecting terminal 2.3.

The procedure for assembling a piezoelectric vibrator having this configuration can be performed using a semiconductor manufacturing method similar to that for a DHD type diode, so a description thereof will be omitted.

Furthermore, since the piezoelectric vibrator according to the present invention is constructed as described above, it has the following effects.

(2) Since the metal substrate of the piezoelectric vibrator chip is constructed by integrally connecting the diaphragm portion and the frame portion, the metal substrate can be manufactured using high-precision semiconductor manufacturing technology such as etching.

Therefore, even if the diaphragm section is downsized, the connection section (in the embodiment, the arm) with the frame section can be formed accurately at an appropriate position according to the vibration mode, and it becomes easy to increase the frequency of the piezoelectric vibrator chip.

(2) Since the metal substrate has a structure in which the diaphragm part and the frame part are integrally connected, the number of parts can be reduced due to integration, and the overall structure can also be made smaller.

■Since the piezoelectric vibrator chip and connection terminals are sealed with glass, they are more reliable than conventional mounting structures using simple resin packages, and are cheaper than hermetic seals. The vibrator can achieve both cost and reliability.

■Since the piezoelectric vibrator chip has a circular shape and no directionality,
There is no need to align the directions of the chips, so assembly of the piezoelectric vibrator can be greatly simplified, reducing the number of man-hours and the production cost associated with it.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a piezoelectric vibrator showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing the components of the piezoelectric vibrator in detail. 1... Piezoelectric vibrator chip, 2.3... Connection terminal, 4
-...Glass bulb, 5...Metal substrate. 6... Piezoelectric member, 7... Upper electrode, 9... Vibration plate part, 10... Frame part. Patent applicant Murata Manufacturing Co., Ltd. Representative Patent attorney Shiro Nakajima Figure 1

Claims (3)

[Claims] (1) A piezoelectric vibrator chip having a circular outer shape with a piezoelectric member formed on the surface of a metal substrate where the diaphragm part is integrally connected to the frame part and an upper electrode formed thereon, and a pair of connections. Consisting of a terminal and a glass bulb for sealing, one of the connecting terminals is brought into contact with the upper electrode and the other with the frame part on the back side of the piezoelectric vibrator chip in a state that does not inhibit the vibration of the diaphragm part, and the glass bulb is A piezoelectric vibrator characterized by being sealed. (2) Claim (1) characterized in that the metal substrate has a configuration in which a diaphragm portion is provided at the center and a frame portion is provided around the periphery, and both are integrally connected by a pair of arms. Piezoelectric vibrator described in. (3) The pair of connection terminals have a convex portion formed around the cylindrical head, and the convex portion of one connection terminal is connected to the upper electrode on the frame portion of the other connection terminal. The convex portions are in contact with the frame portions on the back side of the chip, and the diaphragm portion is suspended in a space formed between the recessed portions at the center of the heads of both connection terminals. A piezoelectric vibrator according to claim (2).