JPH09148646A - Retaining method of piezoelectric transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakdown of an element due to abnormal driving, without deteriorating the efficiency of a piezoelectric transformer, by setting the retaining position of the piezoelectric transformer, at the node position of an oscillation mode in the length direction, and at a specific position distant from the center in the width direction. SOLUTION: Driving electrodes 5, 6 are formed on both surfaces in the thickness direction of a driving part 4 of a piezoelectric transformer main body 3. In the case that vibrating of the driving electrodes 5, 6 is a λ mode, 2/3 of the length turns to the driving electrodes 5, 6, in the 1/2, 3/2λ mode of the length of the piezoelectric transformer main body 3. A part 7 of the main body 3 where the driving electrodes 5, 6 are not formed is a power generating part, and a power generating electrode 8 is formed on the end surface of the part 7. The main surface of the piezoelectric transformer main body constituted in the above manner is supported by retaining part members 9. At positions which are 1/5 or more of the width dimension W distant from the center of the width direction, the piezoelectric transformer is supported by the retaining part members 9, form above the bellow.

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 for a high voltage and small current power source of electronic equipment such as a television receiver and a liquid crystal backlight.

[0002]

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

FIG. 5 shows a strip-shaped so-called Rosen type piezoelectric transformer. In FIG. 5, reference numeral 4 denotes a drive portion corresponding to half the length direction of the piezoelectric transformer main body 3, and excitation electrodes 5 and 6 are formed on both sides in the thickness direction thereof. In addition, the excitation electrodes 5 and 6
A portion 7 where no is formed is a power generation portion, and a power generation electrode 8 is formed on the end surface thereof.

Since the driving principle of the piezoelectric transformer is well known, detailed description will be omitted. In general, as the length vibration mode to be driven, the λ mode in which two node positions 1 are formed is used, and the displacement distribution 2 is as shown in FIG. The support position at this time is set to the node position 1 of the length vibration so as not to disturb the vibration, but in the width direction, the entire width is supported by the support member 9 as shown in FIG. 7 or the center as shown in FIG. It was general that a part was supported by a supporting member 9.

[0005]

However, in the conventional structure as described above, when the whole is supported as shown in FIG. 7, even in the mode of length vibration, displacement in the width direction corresponding to the Poisson's ratio occurs. As a result, since the vibration in the length direction is suppressed, there is a problem that the Q at the time of resonance of the length vibration is lowered and the efficiency of the piezoelectric transformer is lowered. 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-described efficiency deterioration. In this case, however, a voltage having a higher frequency component than usual is applied to the piezoelectric transformer when the drive circuit or load is abnormal. When applied, resonance also occurs in the vibration mode in the width direction, and in the worst case, the piezoelectric transformer is damaged.

The present invention solves the above-mentioned conventional problems and prevents damage due to abnormal driving of the piezoelectric transformer without impairing the efficiency of the piezoelectric transformer, resulting in stable and highly reliable piezoelectric transformer. The purpose is to provide.

[0007]

In order to achieve this object, a method of supporting a piezoelectric transformer according to the present invention comprises a strip-shaped piezoelectric element, an excitation electrode formed on the main surface of the strip-shaped piezoelectric element, and the strip-shaped piezoelectric element. In a Rosen type piezoelectric transformer including a power generation electrode formed on a portion of the piezoelectric element where the excitation electrode is not formed, a length direction of the piezoelectric transformer is at a node position of at least one vibration node, and a width direction thereof has a width dimension 1 from a center. It supports a position separated by / 5 or more.

With this structure, the piezoelectric transformer can be prevented from being damaged by resonance in the width direction without disturbing the resonance of the vibration mode when the piezoelectric transformer is driven and even when an abnormal signal containing a high frequency component is applied. It is possible to provide a highly efficient piezoelectric transformer that is stable in performance.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention comprises 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 including a power generation electrode formed in a non-formed portion, the length direction is at least 1
This is a method for supporting a piezoelectric transformer that supports the position of one vibration node in the width direction at a distance of ⅕ or more of the width dimension from the center. According to this method, the piezoelectric transformer 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 support positions in the width direction are alternately provided with respect to the node positions. According to this method, the piezoelectric transformer is provided. 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 of supporting the piezoelectric transformer according to the present embodiment. FIG. 1 is a perspective view showing a supporting state in the λ mode described in the related art, and FIG. 2 is a perspective view showing a piezoelectric transformer in the 3/2 λ mode in which there are three node positions in the length vibration mode and the supporting state thereof. 3 and 4 show the node position 1 and the displacement distribution 2 of the vibration mode. Further, FIG. 4 shows the node position 1 and the displacement distribution 2 of the vibration mode in the width direction W of the piezoelectric transformer. In FIGS. 1, 2 and 3, 3 is a piezoelectric transformer main body, 4 is a drive unit, and excitation electrodes 5 and 6 are formed on both sides in the thickness direction. When the vibration in FIG. 1 is in the λ mode, the excitation electrodes 5 and 6 are 1/2 the length of the piezoelectric transformer main body 3 and 3 / 2λ in FIG.
In the mode, 2/3 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 the end surface thereof. It is the support member 9 that supports the main surface of the piezoelectric transformer body 3 configured as described above.
As shown in FIG. 2, the support member 9 supports the piezoelectric transformer in the vertical direction at a position separated from the center in the width direction by ⅕ or more of the width W. By supporting in this way, a portion having a large displacement amount of the width vibration shown in FIG. 4 is supported by the supporting member, and this vibration is suppressed even if an abnormal signal including a high frequency component is applied and resonance occurs in the width direction. It is possible to prevent damage to the piezoelectric transformer. Further, since the entire width is not supported, the influence on the vibration mode in the length direction in the driven state can be reduced.

The supporting area is preferably as small as possible in order not to disturb the original vibration of the piezoelectric transformer.

When there are two or more support positions, the node position of the vibration mode in the length direction is a position apart from the center by ⅕ or more of the width dimension in the width direction. The distance from the center of the may be different.

[0014]

As described above, according to the present invention, the piezoelectric transformer supporting position is located at the node position of the vibration mode in the length direction of the piezoelectric transformer and in the width direction at a position separated from the center by ⅕ or more of the width dimension. By doing so, it is possible to prevent damage 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 method of supporting the piezoelectric transformer.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a supported 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 a 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 of a supporting state of a conventional piezoelectric transformer.

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

[Explanation of symbols]

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

Claims (2)

[Claims] 1. A Rosen type device comprising 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 where the excitation electrode of the strip-shaped piezoelectric element is not formed. A method of supporting a piezoelectric transformer, wherein a lengthwise direction of the piezoelectric transformer is a node position of at least one vibration node, and a widthwise direction of the piezoelectric transformer is at a position ⅕ or more of a width dimension away from the center. 2. The method for supporting a piezoelectric transformer according to claim 1, wherein when there are two or more node positions of the vibration node, support positions in the width direction are alternately provided with respect to the node positions.