JP2001223405A - Piezoelectric transformer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve shock resistance and reliability of a piezoelectric transformer and a device using the transformer by improving connecting method of an electrode of the transformer and mounting method on a circuit. SOLUTION: A terminal has function which fixes the piezoelectric transformer on a board and connects an external electrode of the transformer with a circuit. One side of the terminal which is in contact with the external electrode is formed in to a spiral spring. As a result, the transformer is fixed on a circuit board without generating troubles such as breakdown of the external electrode of the transformer and vibration of the transformer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transformer, and more particularly, to a piezoelectric transformer used for a piezoelectric inverter for a backlight of a liquid crystal display and a piezoelectric transformer device mounted on a circuit board. It is.

[0002]

2. Description of the Related Art With the spread of various portable electric and electronic devices such as notebook type personal computers, these electric and electronic devices have been required to have higher efficiency, smaller size, thinner, lower power consumption, and reduced electromagnetic noise. Demands are growing. In response to such a trend, miniaturization of various electric and electronic component devices is being studied.

[0003] Focusing on transformers, a piezoelectric transformer has been studied and put into practical use as an alternative to a conventionally used electromagnetic induction transformer. The piezoelectric transformer has a configuration in which a mechanical vibration is generated by applying an input voltage to a vibration unit, and the mechanical vibration is converted into a voltage in a power generation unit and output. Since there is no need for winding, it can be reduced in size and thickness, and has the characteristics of high efficiency and no generation of electromagnetic noise.

Due to this feature, piezoelectric transformers are used in backlight inverter devices for liquid crystal displays of portable equipment such as notebook personal computers. It is also expected to be used for other portable devices.

[0005] As described above, the piezoelectric transformer inevitably involves mechanical vibrations in the use state, so that the element cannot be fixed to a substrate or the like, and the mounting method requires a special structure. . FIG. 3 shows an example of a conventional mounting method of a piezoelectric transformer. FIG. 3 (a) is a perspective view, and FIG.
(B) is a sectional view.

As shown in FIG. 3, an external electrode 15 is provided on a side surface of the substantially plate-shaped piezoelectric transformer 10, and the plate-shaped conductor terminal 12 implanted in the case 14 is connected to the external electrode 15.
Is in contact with. The plate-shaped conductor terminal extends to the bottom surface of the case 14 to form a surface-mounted terminal 16.

The plate-shaped conductor terminal 12 has elasticity,
When the external electrode 15 of the piezoelectric transformer 10 is elastically deformed,
Is pressed against. In other words, the plate-shaped conductor terminal 12 secures conduction between the external electrode 15 of the piezoelectric transformer and the circuit, and is capable of following the vibration of the piezoelectric transformer 10.
It also has a function of supporting the piezoelectric transformer 10.

[0008] In such a piezoelectric transformer device,
In consideration of the mounting work of the piezoelectric transformer in the assembly process, the subsequent aging, and external impact, a plate-shaped conductor terminal 12 having a certain rigidity or more is used.
It is necessary to design so as to strongly press the piezoelectric transformer.

[0009]

However, if the rigidity of the plate-shaped conductor terminal is excessively increased, the vibration of the piezoelectric transformer 10 is hindered, resulting in a decrease in efficiency and an increase in heat generation, and required performance is obtained. There is a possibility that there is no. In addition, an increase in rigidity of the plate-shaped conductor terminal may damage external electrodes of the piezoelectric transformer. For this reason, the rigidity of the plate-shaped conductor terminal as a spring cannot be increased so much, and it has been difficult to improve the shock resistance of the piezoelectric transformer device.

Accordingly, an object of the present invention is to provide a highly reliable piezoelectric transformer device which has high efficiency without impeding vibration of the piezoelectric transformer, does not damage external electrodes of the piezoelectric transformer, and has improved impact resistance. An object is to provide a device using the same.

[0011]

SUMMARY OF THE INVENTION The present invention has been made as a result of studying the structure of the terminal plate for mounting a piezoelectric transformer on a circuit board. That is, the present invention provides a piezoelectric transformer device in which a piezoelectric transformer is mounted on a circuit board through a terminal plate having a function of holding the piezoelectric transformer on a circuit board and connecting external electrodes of the piezoelectric transformer to a circuit. The side of the terminal plate in contact with the external electrode of the piezoelectric transformer constitutes a spiral spring, and the end is fused and connected to the external electrode of the piezoelectric transformer by soldering or the like, and the side connected to the circuit constitutes a plate-like terminal. The piezoelectric transformer device is melt-connected to a circuit by soldering or the like.

Further, according to the present invention, the piezoelectric transformer is mounted on the circuit board via a plurality of terminal plates having a function of holding the piezoelectric transformer on the circuit board and connecting external electrodes of the piezoelectric transformer to the circuit. In the piezoelectric transformer device, at least one of the plurality of terminal plates has a configuration of the spiral spring described above. According to another aspect of the invention, there is provided an electric / electronic apparatus using the above-described piezoelectric transformer device.

[0013]

Since the terminal of the present invention has a spring structure at the portion in contact with the piezoelectric transformer as described above, the piezoelectric transformer can be stably held with a constant force. Therefore, no excessive pressure is applied to the external electrodes of the piezoelectric transformer, and the possibility of breakage is extremely small. In addition, since the spiral spring is used, the space occupied by the coil spring is smaller than when using a normal coil-shaped compression spring.
Does not hinder downsizing of the device.

Further, in the conventional plate-shaped terminal, there is a possibility that a change over time such as metal fatigue and creep occurs during use of the device, and it is impossible to secure an electrical connection between the piezoelectric transformer and the circuit board. According to the present invention, the trouble caused by this phenomenon can be extremely reduced.

[0015]

Embodiments of the present invention will be described below with reference to specific examples.

FIG. 1 is a diagram showing an example of an embodiment of the present invention. 2 is an enlarged view of a portion A in FIG. 1. FIG. 2 (a) shows a front view, and FIG. 2 (b)
Indicates the side.

As shown in FIG. 1, this piezoelectric transformer device has a structure in which a piezoelectric transformer 10 having a substantially plate-like shape and an external electrode 15 attached to a side surface is attached to a case 14 via a terminal 11. The side of the terminal 11 connected to the circuit is extended to the bottom surface of the case 14 to form a surface-mounted terminal 16.

As shown in FIG. 2, the terminal 11 is formed in a spiral shape and has a compression spring which is elongated in the thickness direction.
That is, it is a spiral spring, and the contact between the terminal 11 and the external electrode 15 of the piezoelectric transformer 10 is fixed by soldering. Then, by soldering the surface mounting terminals 16 to the board, electrical connection between the external electrodes 15 and a circuit (not shown) on the board can be secured.

Further, in the conventional piezoelectric transformer device shown in FIG. 3, the piezoelectric transformer 10 is placed in contact with the case 14, but according to the present invention, as shown here, the piezoelectric transformer Since the device 10 can be held at a certain distance from the case 14, the factor that hinders vibration is reduced and the characteristics of the device are improved.

As described above, according to the present invention, the piezoelectric transformer can be held by the flexible terminal, and the external electrodes of the piezoelectric transformer can be damaged without obstructing the vibration of the piezoelectric transformer. In this state, the impact resistance of the device can be improved. In addition, since the external electrodes 15 of the piezoelectric transformer 10 are soldered, unlike a simple contact, it is possible to suppress a contact failure due to a temporal change of the external electrodes 15.

Although the example in which the piezoelectric transformer 10 is mounted on the case 14 is shown here, it is needless to say that the piezoelectric transformer 10 can be directly mounted on a circuit board. Also, in this example, spiral connection spring terminals were used for all connection points.
A certain effect can be obtained even if not all have such a structure.

[0022]

As described above, according to the present invention, the shock resistance and the high reliability can be obtained without hindering the vibration of the piezoelectric transformer, with high efficiency, without damaging the external electrodes of the piezoelectric transformer. It is possible to provide a piezoelectric transformer device provided with the device, and a device using the same.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an embodiment of the present invention.

FIG. 2 is an enlarged view of a joint between an external electrode and a terminal of the piezoelectric transformer according to the embodiment of the present invention. FIG.
(B) shows a side surface.

FIG. 3 is a perspective view showing an example of a conventional piezoelectric transformer.
(A) is a perspective view, FIG.3 (b) is sectional drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Piezoelectric transformer 11 Spiral spring terminal 12 Plate-shaped terminal 13 Circuit board 14 Case 15 External electrode 16 Surface mounting terminal

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tetsuo Yoshida 6-7-1, Koriyama, Taishiro-ku, Sendai-shi, Miyagi Pref.

Claims (2)

[Claims] 1. A piezoelectric transformer device having a piezoelectric transformer mounted on a circuit board via a terminal plate having a function of holding the piezoelectric transformer on a circuit board and connecting external electrodes of the piezoelectric transformer to a circuit. The side of one of the terminal plates that contacts the external electrode of the piezoelectric transformer forms a spiral spring, and the end is fused and connected to the external electrode of the piezoelectric transformer by soldering or the like, and the side connected to the circuit is: A piezoelectric transformer device comprising a plate-like terminal and being melt-connected to a circuit by soldering or the like. 2. An electric / electronic device using the piezoelectric transformer device according to claim 1.