JPS6288411A - Piezoelectric vibrator - Google Patents

Abstract

PURPOSE:To avoid almost crack or chipping giving adverse effect on the vibration characteristic by designing the titled vibrator that the film thickness of the piezoelectric thin film formed on the vibration substrate is made thinner toward the end. CONSTITUTION:The titled vibrator consists of the vibration substrate 1, a piezoelectric thin film 2 and an electrode film 3. The substrate 1 is formed incorporatedly with a holding frame 4 and couplers 5, 5. The thickness of the piezoelectric thin film 2 is formed thinner toward the end at the end long both the long sides on the substrate 1. Since the piezoelectric thin film 2 is formed by the vapor growth method such as sputtering, the growth of the piezoelectric thin film 2 at the part close to the mask end is suppressed by making the thickness of the mask sufficiently thick and the film thickness of the piezoelectric thin film at the end on the substrate 1 is made thinner toward the end.

Description

DETAILED DESCRIPTION OF THE INVENTION (AL technical field) This invention relates to
The present invention relates to a piezoelectric vibrator that is constructed by forming a piezoelectric thin film such as O, and utilizes an appropriate vibration mode depending on the frequency, such as bending vibration or spreading vibration.

(bl) Conventional technology and its drawbacks
A piezoelectric vibrator formed with a piezoelectric thin film such as O or the like is often used as an oscillator for color synchronization of a TV. If this is the case,
This is because such a piezoelectric vibrator has better precision than using piezoelectric ceramics (and can be manufactured at a lower cost than using crystal). An example of this piezoelectric vibrator is shown in Fig. 2. , consists of a vibrating substrate 1, a piezoelectric thin film 2, and an electrode film 3.The vibrating substrate 1 is a rectangular thin plate made of a constant elastic metal material such as Erinvar.The vibrating substrate 1 is surrounded by a frame-shaped support. It is surrounded by a frame 4 and supported by this holding frame 4 by connectors 5.5 installed at the center of both short sides.The piezoelectric thin film 2 is made of zinc oxide ZnO.
A piezoelectric material such as the above is formed into a thin film on the vibrating substrate 1 by a method such as sputtering. The electrode film 3 is
Further, it is a metal thin film such as aluminum, which is formed on the piezoelectric thin film 2 with open ends by a method such as vapor deposition.

However, in such a conventional piezoelectric vibrator, as shown in FIG. This has the disadvantage that cranks and chips are more likely to occur in the circuit, which adversely affects the liveliness characteristics such as frequency shifts, spurious emissions, and poor linearity, resulting in a deterioration in product quality. This is mask matching 1 for forming electrode film 3! Despite the fact that masks and T-tools often come into contact with the edges of the vibrating substrate 1 during assembly work such as dividing the substrate and attaching it to the gate, the piezoelectric thin film 2 formed by sputtering etc. This is because stress was concentrated at the end and the i#i 42 became weak.

(C) Purpose of the Invention This invention has been made in view of the circumstances 1 and 2, and is aimed at reducing the thickness of the piezoelectric thin film formed on the vibrating substrate -1- so that the I9 thickness becomes less than +1 as it approaches the edge. As a result, cracks and chips may occur that adversely affect vibration characteristics.
The purpose is to provide a piezoelectric vibrator that is

(di Structure and Effect of the Invention The piezoelectric vibrator of the present invention comprises a vibrating substrate made of a plate-shaped constant elastic material supported by two or more connectors, a piezoelectric thin film formed on the vibrating substrate, and further comprising: In the piezoelectric vibrator composed of the piezoelectric thin film and the electrode film formed on the piezoelectric thin film, the film thickness of the piezoelectric thin film becomes thinner as it approaches the edge, at least at the end of the side on the vibrating substrate that does not form a coupler. It is characterized by being formed as follows.

When the piezoelectric vibrator of the present invention is constructed as described above, the thickness of the piezoelectric thin film becomes thinner toward the ends, so that significant internal stress can be dispersed at the ends. Therefore, even if a mask for forming an electrode film or a tool used during assembly comes into contact with the edge of the vibrating substrate, there is no fear that the piezoelectric thin film will easily crack or chip. Therefore, in the piezoelectric vibrator of the present invention, the negative influence on the vibration characteristics due to cranking or chipping of the piezoelectric thin film is reduced, so that the quality of the product can be stabilized - toward the yield.

EXAMPLE A case will be described below in which the present invention is applied to a piezoelectric vibrator using a rectangular Elinva as the vibrating substrate 1 and using zinc oxide ZnO as the piezoelectric thin film 2.

1 is a cross-sectional view taken along line A--A in FIG. 2 of a piezoelectric vibrator used in an embodiment of the present invention, and FIG. 2 is a perspective view of the piezoelectric vibrator.

The piezoelectric vibrator of this embodiment is composed of a vibrating substrate 1, a piezoelectric thin film 2, and an electrode film 3. The vibration substrate 1 is a rectangular thin plate similar to the conventional one, and is formed integrally with the holding frame 4 and the connectors 5, 5 by applying precision chemical etching to a thin plate of Elinva. The piezoelectric thin film 2 is formed at the ends along both circles of the vibrating substrate 11- so that the film thickness becomes thinner as it approaches the ends. Vibration board 1
Since the piezoelectric thin film 2 is formed on the top by a vapor phase growth method such as sputtering, a mask is placed in contact with the edge of the vibrating substrate 1 to cover unnecessary parts when forming the bottom.
By making this mask thick enough,
The growth of the piezoelectric thin film 2 near the edges of the mask can be suppressed, and the thickness of the piezoelectric thin film at the edges of the vibrating substrate 1 can be formed to become thinner as it approaches the edges. The electrode film 3 is
As in the past, it is formed on this piezoelectric thin film 2 with open ends. Note that the piezoelectric thin film 2 and the electrode film 3 are connected to the vibration substrate 1-1.
=, but also - on the holding frame 4 via one connector 5.
The drawn electrode film 3
The terminal can be taken out from the '' part. Further, the vibration substrate 1 also serves as the other electrode of the piezoelectric vibrator corresponding to the electrode film 3.

In the example, the portion where the film thickness of the piezoelectric thin film 2 is reduced is the vibrating substrate 1.
The reason why the ends are along both long sides is that the direction of bending vibration of the piezoelectric vibrator and spreading vibration in the direction of the short side is perpendicular to the line connecting the coupler 5.5, so the amount of displacement is This is because if a crank or a chip occurs in the piezoelectric thin film 2, the effect will be greatest at the ends along both long sides where the number of defects increases. Therefore, even at the end along the short side of the vibrating substrate 1 on which the couplers 5, 5 are formed, the thickness of the piezoelectric thin film 2 becomes 1V as it approaches the end. 1. It may be formed into sea urchin.

The piezoelectric vibrator of the embodiment configured as above is as follows.
Vibration L'; Assuming that the end of the electrode film 3 is in contact with the end of the electrode film 3 at t7, Y), 1/! of the piezoelectric thin film 2! The stress in part 1 is 11 (! Goodbye 1 [, so the crank and the missing number 1 should not easily be throated (). Therefore, this actual h1!! example piezoelectric 1 moving center 51, Since there is no fear that cracks or chips 11 in the piezoelectric thin film 2 may cause vibrations 91 to have an adverse effect on the performance, the quality of the product is improved by improving the stability of the product. I can do it.

In addition, similarly to the present invention, in order to prevent the piezoelectric thin film 2 from being cracked or chipped 11, a piezoelectric thin M is provided at the end of the vibrating substrate.
tV is the invention of a piezoelectric device that does not form a Q and has a L shape.
). So, this invention and illumination! Then, a piezoelectric thin film was formed on the i5i:1 part of the vibrating substrate 1-U, [1
If this piezoelectric film is formed so that the film thickness becomes thinner as it approaches the ends even at the ends of the 117 crotches, it will be possible to prevent the piezoelectric thin film from being cranked or chipped by /1°. The results can be made more reliable.

[Brief explanation of drawings]

1 is a cross-sectional view taken along the direction A-A in FIG. 2 of a piezoelectric vibrator used in an embodiment of the present invention, FIG. 2 is a perspective view of the piezoelectric vibrator, and FIG. 3 is a cross-sectional view of a conventional piezoelectric vibrator. It is a cross-sectional view taken in the direction of figure A-A. 1-vibrating substrate, 2-piezoelectric thin film, 3-electrode film.

Claims (1)

[Claims] (1) A vibrating substrate made of a plate-shaped constant elastic material supported by two or more connectors, a piezoelectric thin film formed on this vibrating substrate, and an electrode film formed on this piezoelectric thin film. A piezoelectric vibrator constructed of a piezoelectric vibrator, characterized in that the thickness of the piezoelectric thin film is formed to become thinner as it approaches the edge, at least at the end of the side on which the coupling element is not formed on the vibrating substrate. .