JPH1022537A - Element for piezoelectric transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a time for soldering a lead to an electrode of an element by forming a thermal land connecting a lead in an input/output electrode. SOLUTION: A thermal land 7 is formed in input electrodes 1, 2 and an output electrode 3 of an element 6 for a piezoelectric transformer. The thermal land 7 is an island-like electrode which is partially linked to an electrode in a circumference, and a lead 5 is connected to the island-like electrode by soldering 4. Since an island-like electrode at a center of the thermal land 7 has few parts linked to an electrode in a circumference, heat diffusion to a circumference lowers remarkably and an area can be made small and fixed. Therefore, a temperature of an electrode can be raised up to a temperature to allow solder to wet enough in a short time and a time for the soldering 4 can be reduced. Furthermore, if a formation position of the thermal land 7 is a position which is a node of a driving vibration mode, the position is a steady point in principal and defect such as peeling caused by vibration of the lead 5 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an element for a piezoelectric transformer, and more particularly to an element for a Rosen type piezoelectric transformer.

[0002]

2. Description of the Related Art In a liquid crystal display panel used in a portable notebook personal computer or the like, a cold cathode tube called a backlight is used as a light emitting source, and the cold cathode tube is turned on to emit light. In order to maintain this, a Rosen-type piezoelectric transformer element is used. This Rosen-type piezoelectric transformer element has an advantage that the thickness of the entire power supply module can be reduced as compared with a winding transformer having the same output.

FIG. 1 shows a structural example of a Rosen-type piezoelectric transformer element. The shape of the element is a rectangular plate as shown in FIG. 1 and the left half thereof has primary and secondary input electrodes 1, 2 on its upper and lower surfaces.
Is formed, and a secondary-side output electrode 3 is formed on the right half end face. To polarize this element, first, a high voltage is applied between the input electrodes 1 and 2 to polarize the first region in the vertical direction (thickness direction), and then, between the input electrode 1 or 2 and the output electrode 3. To polarize the second region in the longitudinal direction. When an AC voltage is applied through the lead wire 5 connected by soldering 4 between the input electrodes 1 and 2 of the polarized element, the element is mechanically moved to the first position according to the piezoelectric material constant and dimensions. Vibrates in the area,
The vibration is converted into a voltage in the second region, and a high-voltage AC voltage boosted from the output electrode 3 via the lead wire 5 connected by soldering 4 can be taken out.

[Problems to be solved by the invention]

However, when the lead wire 5 is soldered to the input electrodes 1 and 2 and the output electrode 3 formed as described above, the temperature of the electrode at the soldering location must be increased until the solder is sufficiently wetted. It takes a long time for the temperature to rise due to the large electrode area. As a result, a considerable amount of time is required for soldering, and there is a problem that productivity is poor. In addition, if a long time is required for the soldering time, silver cracks occur in the electrode containing silver as a main component, and there is a problem that the soldering is likely to be defective.

The present invention has been made in view of the above-mentioned problems of the piezoelectric transformer element, and its object is to
An object of the present invention is to provide a piezoelectric transformer element that can reduce the time for soldering a lead wire to an element electrode.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, soldered lead wires to input / output electrodes formed on a piezoelectric transformer element. It has been found that the formation of the thermal land to be connected can shorten the time for soldering the lead wire to the electrode, leading to the following invention.

That is, the present invention relates to (1) a piezoelectric transformer element having a first region which forms an input electrode and is polarized in a thickness direction and a second region which forms an output electrode and is polarized in a longitudinal direction. A thermal land for connecting a lead wire is formed in the input / output electrode. The present invention provides a piezoelectric transformer element (Claim 1). The element is formed at a position corresponding to the node (1). This will be described in more detail below.

As described above, thermal lands as shown in FIGS. 2 and 3 are formed on the input / output electrodes of the piezoelectric transformer element. As shown in the figure, the thermal land is an island-shaped electrode partially connected to a surrounding electrode, and a lead wire is connected to the island-shaped electrode by soldering. Because the island-shaped electrode at the center of this thermal land has few parts connected to the surrounding electrodes, the diffusion of heat to the surroundings is significantly lower than without the thermal land, and its area is small and constant. Therefore, the temperature of the electrode can be raised to a temperature at which the solder is sufficiently wet in a short time, and the time for soldering can be shortened. The shape of this thermal land is shown in FIG. 4 in addition to FIG. 3, but it is not particularly limited as long as it is connected to the surrounding electrodes and has an island shape.

The thermal land is formed at a position corresponding to a node of the driving vibration mode (claim 2). To raise the input voltage, the position of the thermal land does not need to be particularly limited. However, since the position corresponding to the node of this vibration is a position that is in principle a fixed point, defects such as peeling or falling off due to vibration of the lead wire Can be suppressed, and it becomes a more preferable position. If there is a thermal land at a position corresponding to the node of the drive vibration mode, there is no need to search for that position, and the lead wire can always be quickly and accurately soldered to that position, so that the time for soldering can be reduced.

With the above-described piezoelectric transformer element, a lead wire can be soldered to a required position of an electrode of the element in a short time.

[0011]

EXAMPLES Examples of the present invention will be described below together with comparative examples.
The invention is explained in more detail by means of the figures.

(Example) Pb (Zr, Ti) O ₃ -based piezoelectric material powder is used, water and a binder are blended with the powder, a slurry is formed by a ball mill, and a rectangular parallelepiped piezoelectric ceramic is formed from the slurry. And fired. Input electrodes 1 and 2 having thermal lands 7 as shown in FIGS. 2 and 3 on the upper and lower surfaces of the left half of the obtained sintered body at one-fourth of the total length L of the element, respectively, and the side surfaces at the longitudinal end portions. The output electrode 3 having the thermal land 7 is printed with an Ag paste,
The piezoelectric transformer element 6 before baking and polarization at 100 ° C.
This was produced.

Next, the lead wire 5 is soldered to the thermal lands 7 of the input electrodes 1 and 2 by soldering 4, and the lead wire 5 is further soldered to the thermal lands 7 of the output electrode 3 to 100 elements. The time required for soldering was calculated to be 8 minutes.

(Comparative Example) Using the same material and manufacturing method as in the example, 100 piezoelectric transformer elements 6 having no thermal land on the electrode were manufactured. The lead wire 5 was soldered to 100 of the elements in the same manner as in the example, and the time required for the soldering was similarly determined. The result was 15 minutes.

As is apparent from the above results, the time required for soldering in the embodiment can be reduced to about half that in the comparative example.

[0016]

As described above, with the Rosen-type piezoelectric transformer element according to the present invention, the time for soldering the lead wire to the electrode of the element can be reduced, and as a result, the productivity can be increased. Now you can. In addition, silver cracking due to solder can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a conventional Rosen-type piezoelectric transformer element.

FIG. 2 is a perspective view showing a Rosen-type piezoelectric transformer element of the present invention.

FIG. 3 is a plan view showing a Rosen-type piezoelectric transformer element of the present invention.

FIG. 4 is a diagram showing an example of a thermal land formed on an electrode in a Rosen-type piezoelectric transformer element of the present invention.

[Explanation of symbols]

 1, 2 input electrode 3 output electrode 4 soldering 5 lead wire 6 element 7 thermal land

Claims (2)

[Claims] 1. An element for a piezoelectric transformer having a first region forming an input electrode and polarized in a thickness direction and a second region forming an output electrode and polarized in a longitudinal direction. And a thermal land for connecting a lead wire to the piezoelectric transformer element. 2. The element for a piezoelectric transformer according to claim 1, wherein the thermal land is formed at a position corresponding to a node of the driving vibration mode.