JP3346135B2 - Method of supporting piezoelectric transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supporting a piezoelectric transformer used in a high-voltage, low-current power supply of electronic equipment such as a television receiver and a liquid crystal backlight.

[0002]

2. Description of the Related Art A conventional method for supporting a piezoelectric transformer will be described.

FIG. 5 shows a so-called Rosen type piezoelectric transformer having a strip shape. In FIG. 5, reference numeral 4 denotes a driving portion corresponding to a half in the length direction of the piezoelectric transformer main body 3, and excitation electrodes 5 and 6 are formed on both surfaces in the thickness direction. Excitation electrodes 5 and 6
The portion 7 where is not formed is a power generation portion, and a power generation electrode 8 is formed on an end face thereof.

[0004] Since the driving principle of the piezoelectric transformer is known, a detailed description is omitted. In general, a λ mode in which two node positions 1 are used is used as a driving length vibration mode, and a displacement distribution 2 is as shown in FIG. At this time, the supporting position is set to the node position 1 of the length vibration so as not to hinder the vibration. In the width direction, the whole width is supported by the supporting member 9 as shown in FIG. The part was generally supported by a support member 9.

[0005]

However, in the conventional configuration as described above, if the entire structure is supported as shown in FIG. 7, a displacement in the width direction corresponding to the Poisson's ratio occurs even in the mode of length vibration. As a result, there is a problem that the Q at the time of resonance of the length vibration is reduced to suppress the vibration in the length direction, and the efficiency of the piezoelectric transformer is reduced. There is also a method of supporting the central portion in the width direction as shown in FIG. 8 in order to prevent the above-mentioned reduction in efficiency. When voltage is applied, resonance occurs even in a vibration mode in the width direction, and in the worst case, the piezoelectric transformer is damaged.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and prevents the piezoelectric transformer from being damaged due to abnormal driving without impairing the efficiency of the piezoelectric transformer, and as a result, a stable and highly reliable piezoelectric transformer. The purpose is to provide.

[0007]

In order to achieve this object, a method for supporting a piezoelectric transformer according to the present invention comprises a rectangular piezoelectric element, an excitation electrode formed on the main surface of the rectangular piezoelectric element, In a Rosen-type piezoelectric transformer having a power generation electrode formed on a portion of the piezoelectric element where the excitation electrode is not formed, the length direction is a node position of at least one vibration node, and the width direction is one width dimension larger than the center. It supports a position separated by / 5 or more.

With this configuration, it is possible to prevent breakage of the piezoelectric transformer due to resonance in the width direction even if an abnormal signal including a high frequency component is applied without preventing the resonance of the vibration mode when driving the piezoelectric transformer. It is possible to provide an efficient piezoelectric transformer that is stable in performance.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a strip-shaped piezoelectric element, an excitation electrode formed on a main surface of the strip-shaped piezoelectric element, and an excitation electrode of the strip-shaped piezoelectric element. In a Rosen-type piezoelectric transformer having a power generation electrode formed on a non-formed portion, the length direction of the transformer is at least one.
This is a method of supporting a piezoelectric transformer that supports a node position of one vibration node in the width direction at least 1/5 of the width dimension from the center. According to this method, an efficient piezoelectric transformer that is stable in performance and efficient. Can be provided.

According to a second aspect of the present invention, when there are two or more node positions of the vibration node, the supporting positions in the width direction are provided alternately with respect to the node positions. Can be stably supported, and vibration in the width direction can be suppressed.

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a method for supporting a piezoelectric transformer according to the present embodiment. FIG. 1 is a perspective view showing a support state in a λ mode described in the related art, and FIG. 2 is a perspective view showing a piezoelectric transformer in a 3 / 2λ mode in which there are three node positions in a length vibration mode and a support state thereof. FIGS. 3A and 3B show a node position 1 and a displacement distribution 2 in the vibration mode. FIG. 4 shows a node position 1 and a displacement distribution 2 in a vibration mode in the piezoelectric transformer width direction W. 1, 2 and 3, reference numeral 3 denotes a piezoelectric transformer main body, 4 denotes a drive unit, and excitation electrodes 5 and 6 are formed on both surfaces in the thickness direction. When the vibration in FIG. 1 is in the λ mode, the excitation electrodes 5 and 6 are の of the length of the piezoelectric transformer main body 3 and 3 / 2λ in FIG.
In the mode, two thirds of the length becomes the excitation electrodes 5 and 6.
A portion 7 of the piezoelectric transformer main body 3 where the excitation electrodes 5 and 6 are not formed is a power generation portion, and a power generation electrode 8 is formed on an end surface thereof. The support member 9 supports the main surface of the piezoelectric transformer main body 3 configured as described above.
As shown in FIG. 2, the piezoelectric transformer is vertically supported by a support member 9 at a position which is at least 1/5 of the width W from the center in the width direction. By supporting in this manner, the portion where the displacement amount of the width vibration shown in FIG. 4 is large is supported by the support member, and even if an abnormal signal including a high frequency component is applied and resonance occurs in the width direction, this vibration is suppressed. Thus, the breakage of the piezoelectric transformer can be prevented. Further, since the entire width is not supported, the influence on the vibration mode in the longitudinal direction of the driving state can be reduced.

The supporting area is preferably as small as possible so as not to hinder the original vibration of the piezoelectric transformer.

When there are two or more support positions, the node position of the vibration mode in the longitudinal direction, if the position is at least 1/5 of the width dimension from the center in the width direction, the width direction depends on the support position. The distance from the center of the object may be different.

[0014]

As described above, according to the present invention, the position of the node of the vibration mode in the length direction of the piezoelectric transformer and the position which is more than 1/5 of the width dimension from the center in the width direction are the piezoelectric transformer supporting positions. By doing so, it is possible to prevent breakage due to abnormal driving of the element without impairing the efficiency of the piezoelectric transformer, and as a result, it is possible to provide a stable and highly reliable piezoelectric transformer supporting method.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a support state of a λ-mode piezoelectric transformer according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a support state of a 3 / 2λ mode piezoelectric transformer according to an embodiment of the present invention.

FIG. 3 is a diagram showing a displacement distribution of a general 3 / 2λ mode piezoelectric transformer.

FIG. 4 is a diagram showing a displacement distribution of a general vibration mode in the width direction.

FIG. 5 is a perspective view of a general λ mode piezoelectric transformer.

FIG. 6 is a diagram showing a displacement distribution of a general λ-mode piezoelectric transformer.

FIG. 7 is a perspective view showing a support state of a conventional piezoelectric transformer.

FIG. 8 is a perspective view of a support state of a conventional piezoelectric transformer.

[Explanation of symbols]

 Reference Signs 1 node position 3 piezoelectric transformer main body 5 excitation electrode 6 excitation electrode 8 power generation electrode 9 support member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 55-124873 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 41/107

Claims (2)

(57) [Claims] 1. A rosen type including a strip-shaped piezoelectric element, an excitation electrode formed on a main surface of the strip-shaped piezoelectric element, and a power generation electrode formed on a portion of the strip-shaped piezoelectric element where the excitation electrode is not formed. A method of supporting a piezoelectric transformer, wherein a length direction of the piezoelectric transformer is a node position of at least one vibration node, and a width direction of the piezoelectric transformer is a position which is at least 1/5 of a width from a center. 2. The piezoelectric transformer supporting method according to claim 1, wherein when there are two or more node positions of the vibration node, supporting positions in the width direction are alternately provided with respect to the node positions.