JPH08125487A - Piezoelectric vibrator - Google Patents

Abstract

PURPOSE: To provide the piezoelectric vibrator suitable for measurement of a specific gravity of a conductive liquid without immersing an electrode film of a piezoelectric chip to a conductive liquid. CONSTITUTION: An electrode film 2 is not formed to a side of a piezoelectric chip 1 to be immersed in a conductive liquid 4 and a metal 3 not corroded by the conductive liquid 4 such as Au or Pt is immersed in the conductive liquid 4 and a lead wire is connected to the metal 3. A couple of electrodes are provided to a side of the piezoelectric chip not immersed in the liquid and the other side is immersed in the conductive liquid. Furthermore, two sets of excitation are attained by using the two methods in common.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a piezoelectric vibrator suitable for measuring the specific gravity of a conductive liquid.

[0002]

2. Description of the Related Art Conventionally, in measuring specific gravity, a specific gravity meter made of glass or the like is floated in a liquid and the scale of a portion contacting the liquid surface is read.

However, the specific gravity meter made of glass cannot always measure the charge amount of a lead battery or the like in an automobile or the like. The amount of charge can be constantly measured by connecting the piezoelectric vibrator immersed in the liquid to the piezoelectric oscillator and measuring the oscillation frequency. However, there is a problem that the electrode film of the piezoelectric vibrator is damaged when the piezoelectric piece is immersed in the liquid of the lead battery.

[0003]

In order to solve the problems, an electrode film is not formed on the surface of the piezoelectric vibrator that is immersed in the liquid, and a metal electrode is used as a lead terminal through the conductive liquid. For the metal electrode in the conductive liquid, a metal such as Au or Pt that is not corroded by the conductive liquid is used. In addition, it is completely unnecessary to immerse the electrodes in the conductive liquid by providing a pair of electrodes on the surface of the piezoelectric vibrator that is not immersed in the conductive liquid and immersing the opposite surfaces in the conductive liquid. No consideration was given to the membrane and the metal electrode, and the problem was solved by taking these measures.

[0004]

In the case of a lead battery, it is known that the charge amount of the battery has a correlation with the specific gravity of the conductive liquid of the battery. On the other hand, in the piezoelectric vibrator in which at least one surface of the above-mentioned piezoelectric piece is brought into contact with a conductive liquid, there is a correlation between the specific gravity of the conductive liquid and the oscillation frequency. An example showing this is shown in FIG. In the case of lead batteries, the conductive liquid is dilute sulfuric acid. The specific gravity when fully charged is about 1.28, the specific gravity at the end of discharge is about 1.08, and the specific gravity difference is about 0.2. The rate of change of the oscillation frequency when the above-mentioned piezoelectric vibrator is used is about 200 × 10 ⁻⁶ to 300 × 10 ⁻⁶ . FIG. 4 is a graph showing the relationship between the specific gravity of the conductive liquid and the oscillation frequency of the example.

[0005]

EXAMPLE FIG. 1 shows a sectional view of a basic mold of an example. The metal electrode 3 is immersed in the conductive liquid 4 in a container 5 filled with the conductive liquid 4, and the surface of the piezoelectric piece 1 of the single-sided electrode film on which the electrode film is not present is floated so as to touch the conductive liquid 4. However, in this form, it is difficult to fix the piezoelectric piece 1, and the electrode film 2 is attached to the conductive liquid 4.
It is difficult to prevent it from getting wet with.

FIG. 2 shows a practically improved embodiment.
In order to make up for the drawback of FIG. 1, the piezoelectric piece 1 was fixed to the enclosure 6 so that liquid would not leak. Further, the metal electrode 3 in the conductive liquid was also incorporated and fixed in the enclosure 6, and the metal electrode 3 in the conductive liquid also served as protection of the piezoelectric piece 1. By integrating and making it strong like this, handling becomes convenient and it can be used as a sensor.

FIG. 3 shows a practically improved embodiment. The electrode film 2 shown in FIG. 2 is divided into two parts, and independent lead lines of the electrodes are formed. By doing so, not only two pairs of electrodes can be formed between the two respective electrode films 2 and the metal electrode 3 in the conductive liquid, but also two pairs of electrode films can be used and the S mode oscillation can be achieved. By doing so, the metal electrode 3 in the conductive liquid becomes unnecessary, and the handling becomes more convenient.

The metal electrode 3 can be made of any material that is resistant to corrosion, such as Au and Pt. Further, as the material of the piezoelectric piece, crystal, lithium tantalate, niobium or the like can be used. Although not shown in the examples, the oscillation frequency changes abruptly when the piezoelectric piece separates from the conductive liquid surface. By utilizing this, the liquid level can also be monitored.

[0009]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a piezoelectric vibrator without electrode corrosion for continuously and easily measuring the specific gravity of the conductive liquid without immersing the electrode film of the piezoelectric piece in the conductive liquid. Moreover, it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing a basic mold of the present invention.

FIG. 2 is a cross-sectional view showing a practically improved embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a practically improved embodiment of the embodiment of FIG.

FIG. 4 is a graph showing the relationship between the specific gravity of the conductive liquid of the example and the oscillation frequency.

[Explanation of symbols]

 1 Piezoelectric piece 2 Electrode film 3 Metal electrode 4 Conductive liquid 5 Container 6 Enclosure

Claims (6)

[Claims] 1. An electrode film is provided on one surface of a piezoelectric piece, the other surface is in direct contact with the piezoelectric piece through a conductive liquid and the conductive liquid, and the other surface is immersed in the conductive liquid. And a metal electrode formed thereon, and a terminal is provided between the metal electrode and the electrode film. 2. The piezoelectric vibrator according to claim 1, wherein the electrode film of the piezoelectric piece is isolated from the conductive liquid. 3. The piezoelectric element according to claim 1, wherein the metal electrode is integrally attached to a portion of the enclosure around the piezoelectric piece in the conductive liquid, and is attached in the vicinity so as to cover the piezoelectric piece. The piezoelectric vibrator according to the first and second ranges. 4. The piezoelectric vibrator according to claim 1, wherein there are two independent electrode films. 5. The shape of the metal electrode provided in the conductive liquid is any one of a rod shape, a linear shape, a net shape, and a plate shape. , Item 3,
The piezoelectric vibrator according to item 4. 6. The frequency of the piezoelectric vibrator is measured to measure the change in the specific gravity of the conductive liquid, as claimed in claim 1, claim 2, claim 3, claim 4, and claim 4. The piezoelectric vibrator according to the item 5 above.