JPH104225A - Piezoelectric transformer power source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of a piezoelectric transformer power source, and to contemplate miniaturization, low height and low cost. SOLUTION: A piezoelectric transformer has a plurality of inner electrodes inside a piezoelectric ceramic rectangular plate 11, and a set of outer input electrodes 12a and 12b and output electrode 13a and 13b, which are electrically connected to the inner electrodes, are formed on the side of the rectangular plate 11. The above-mensioned piezoelectric transformer and a flexible insulating sheet (FPC) 17, having four linear conductors 16a to 16d which are insulated with each other, and aperture parts 16e to 16h are inserted into a resin-made case 15 having outer protruding parts 15a to 15d, the input electrode, the output electrode and the lower conductor of the FPC 17 are connected one-to-one, and the outer electrode of the piezoelectric transformer is connected to a circuit substrate 14. Besides, after the outer protruding part of the case 15 has been inserted to the aperture of the FPC 17, it is inserted and fixed to the aperture parts 14e and 14h of the circuit substrate 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transformer power supply, and more particularly to a method of extracting electric power by using a flexible insulating sheet having a connection conductor such as a linear conductor and extracting electric power from only one surface to improve reliability. The present invention relates to a piezoelectric transformer power supply that is high in size, small in size and low in height.

[0002]

2. Description of the Related Art A piezoelectric transformer is known as a device using a rectangular plate of a piezoelectric vibrator. At present, ceramic or lithium niobate single crystal is often used as a vibrator used for a piezoelectric transformer.
As shown in the schematic diagram of FIG. 1, input electrodes 12a and 12b capable of inputting and outputting power and an output electrode 13 are formed on the surface or side surface of a piezoelectric ceramic rectangular plate (piezoelectric vibrator) 11, respectively. In general, lead wires 12c, 12d, and 13c are directly soldered to input electrodes 12a and 12b and output electrode 13 formed on piezoelectric ceramic rectangular plate 11, or they are taken out by a spring-like conductor 64. .

Further, as shown in FIG. 7, even when a flexible insulating sheet 71 is used, power is taken out from a plurality of surfaces, so that the reliability is poor and the structure is complicated.

[0004]

In general, there is a strong demand for a piezoelectric transformer having high reliability, miniaturization, reduction in height, and cost reduction. However, the conventional piezoelectric transformer configuration sufficiently satisfies these requirements. There was a drawback that I was not satisfied.

That is, as shown in FIGS. 6 and 7, since lead wires and the like are connected to the piezoelectric transformer, the mounting area and man-hours become enormous even if the piezoelectric transformer is reduced in size and height. Also, if you try to take out the lead only from one surface of the piezoelectric transformer, it will become complicated to route the lead wire,
It was difficult to reduce the reliability and the size. Further, when a flexible insulating sheet is used with the structure of the conventional piezoelectric transformer, electric power is taken out from a plurality of surfaces, so that the structure becomes complicated, lacks reliability, and further reduction in height is not possible. It was possible. As described above, the conventional piezoelectric transformer has a drawback that it is very difficult to sufficiently satisfy the market requirements for miniaturization, reduction in height, and reduction in cost.

Therefore, the present invention improves the drawbacks of the prior art, improves the reliability of the piezoelectric transformer power supply, and
It is intended to reduce the size, height, and cost.

[0007]

According to the present invention, the following piezoelectric transformer power supply can be obtained.

(1) At least one for inputting power
Inserting a piezoelectric transformer having a set of input electrodes and at least one output electrode for extracting power into a case;
In a case in which the piezoelectric transformer is inserted on a circuit board and a piezoelectric transformer power supply in which a circuit component capable of driving and controlling the piezoelectric transformer is mounted, the case has an externally formed convex portion that can be inserted into an opening of the circuit board. It supports a point-like or linear vibration node of the piezoelectric transformer inside,
After the function that can be fixed is formed, the piezoelectric transformer is inserted into the case, and further, between the piezoelectric transformer inserted into the case and the circuit board, each of the input electrode and the output electrode is provided. A flexible insulating sheet having a plurality of connected conductors provided on one surface is interposed, and the flexible insulating sheet has an opening through which a convex portion of the case can be inserted, and the input electrode and the output electrode After the electrodes and the connection conductors are electrically connected one-to-one on one surface of the vibrator rectangular plate of the piezoelectric transformer, and after inserting the convex portion of the case into the opening of the flexible insulating sheet. A piezoelectric transformer power supply, which is inserted and fixed in an opening of the circuit board, and wherein the circuit board and the connection conductor are electrically connected.

(2) The piezoelectric transformer power supply according to the above (1), wherein the external projection of the case and the opening of the circuit board are fixed by bonding.

(3) The outer convex portion of the case is formed of metal, and a land is formed around the opening of the circuit board into which the external convex portion is inserted by using metal foil. The piezoelectric transformer power supply according to the above (1), wherein the protrusion is inserted into the opening of the circuit board and then fixed by melting solder.

(4) The external projection of the case is formed of metal, and the opening of the flexible insulating sheet into which the external projection is inserted and the opening of the circuit board are surrounded by metal foil. The piezoelectric transformer power supply according to (1), wherein a land is formed, and an external convex portion of the case is inserted into an opening of the circuit board, and then fixed by melting solder.

(5) The external protrusion of the case, the land around the opening of the flexible insulating sheet, and the land around the opening of the circuit board are electrically connected to each other (4). The described piezoelectric transformer power supply.

(6) The piezoelectric transformer has at least one set of input electrodes for inputting electric power from a side surface of the vibrator rectangular plate and at least one output electrode for extracting electric power. , (2), (3), (4)
Or the piezoelectric transformer power supply according to (5).

(7) The piezoelectric transformer has at least one set of input electrodes for inputting power from one surface of the vibrator rectangular plate and at least one output electrode for extracting power. ), (2), (3),
The piezoelectric transformer power supply according to (4) or (5).

[0015]

By using the piezoelectric transformer power supply of the present invention, the piezoelectric transformer inserted into the case is connected to the circuit board via a flexible insulating sheet having connection conductors such as linear conductors, so that the circuit can be connected only from one surface. By connecting to the substrate, it is possible to provide a piezoelectric transformer power supply that ensures sufficient reliability, reduces the number of components and the mounting area, and is small in size, low in height, and low in cost.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION
This will be described in the section of Examples.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the piezoelectric transformer according to the present invention will be described below in detail with reference to the drawings.

FIGS. 1A and 1B are a perspective view and a sectional view showing the structure of a piezoelectric transformer according to a first embodiment of the present invention. As shown in FIG. 1, the piezoelectric transformer has a plurality of internal electrodes inside a piezoelectric ceramic rectangular plate 11, and a pair of external input electrodes 12a and 12b which are electrically connected to the internal electrodes. It was formed on both sides of the piezoelectric ceramic rectangular plate 11. Further, external output electrodes 13a, 13b
Also formed on the side surface of the piezoelectric ceramic rectangular plate 11. Here, the size of the piezoelectric ceramic rectangular plate 11 is 40 mm × 6.
mm × 1.5 mm, using PZT ceramics,
The internal electrode is Ag / Pb integrally sintered, and the external electrode is A
g was formed by baking. Next, a case 15 in which the piezoelectric transformer was inserted and supported and fixed at a vibration node was formed by injection molding of a resin. Where 15
a to d are external projections of the case 15. Further, four linear conductors 16a to 16d each insulated and an opening 16e are provided.
To the input electrode 12 of the piezoelectric transformer.
a, 12b, the output electrodes 13a, 13b and the linear conductors 16a to 16d of the flexible insulating sheet 17 are electrically connected one-to-one, and the external electrodes of the piezoelectric transformer are connected to the circuit board 14;
Connected with. Further, the outer convex portions 15a to 15d of the case 15
Was inserted into the openings 16e to 16h, and then inserted and fixed in the openings 14e to 14h of the circuit board 14. Here, reference numeral 18 denotes a circuit component.

Table 1 below shows a comparison of the characteristics of the piezoelectric transformer power supply between the case where a lead wire having a general configuration is used and the case where an FPC is used. At this time, the piezoelectric transformer was an integrally laminated product (10 layers), and a cold cathode tube of φ2 mm × 200 mm was used as a load. As shown in Table 1, even in the case of FPC, characteristics equivalent to those of the conventional lead extraction are obtained.

[0020]

[Table 1]

The results of aging of the piezoelectric transformer power supply are shown in Table 2 below, but no deterioration in characteristics can be confirmed after 1000 hours.

[0022]

[Table 2]

The second embodiment of the present invention is different from the first embodiment in that the external projections 15a to 15d of the case 15 and the openings 14e to 14h of the circuit board 14 are bonded and fixed with an epoxy adhesive. is there.

Table 3 below shows the drop test results of the piezoelectric transformer power supply of the first embodiment and the second embodiment. The good number and the number of breaks do not differ greatly in the length direction of the substrate, but are improved in the vertical direction.

[0025]

[Table 3]

FIG. 2 shows a third embodiment, in which external protrusions 25a to 25a of a box-shaped case 15 into which the piezoelectric transformer can be inserted.
d is formed of a metal, and lands 19 are formed around the openings 24e to 24h of the circuit board 14 into which the projections 25a to 25d are to be inserted by using metal foil. After d was inserted into the openings 24e to 24h of the circuit board 14, it was fixed by melting the solder.

FIG. 3 shows a fourth embodiment, in which the external convex portions 35a to 35a of the box-shaped case 15 into which the piezoelectric transformer can be inserted.
d is an opening 36 of a flexible insulating sheet (FPC) 17 which is formed of metal and inserts the projections 35a to 35d.
After forming lands 19 with metal foil around the openings e to h and the openings 34 e to h of the circuit board 14, and inserting the external projections 35 a to 35 d of the case 15 into the openings 34 e to h of the circuit board 14, It was fixed by melting the solder.

FIG. 4 shows a fifth embodiment, in which the external projections 35a-35 of the box-shaped case 15 into which the piezoelectric transformer can be inserted.
d is an opening 46 of a flexible insulating sheet (FPC) 17 which is formed of metal and inserts the projections 35a to 35d.
Lands 19 are formed by metal foil around the openings e to h and the openings e to h of the circuit board 14, and the external projections 35a to 35d of the case 15 are inserted into the openings 44e to h of the circuit board 14. Thereafter, the solder was fixed by melting. At this time, each is in an electrically connected state, can be easily mounted, and can ensure reliability.

FIGS. 1 to 4 show not only the first to fifth embodiments but also a sixth embodiment in which all the input / output electrodes are formed on the side surfaces of the piezoelectric ceramic rectangular plate. At this time, a linear conductor of a flexible insulating sheet (FPC) was formed at a position where it could be connected to the input / output electrode, and the electrical connection was performed by soldering.

In general, there is a strong demand in the market for an inverter using a piezoelectric transformer in a slender shape having a width of 10 mm or less.
The wiring of the lead wire becomes complicated, and the reliability cannot be sufficiently secured.

FIG. 5 shows a seventh embodiment in which all of the input / output electrodes are formed on one surface (the lower surface in FIG. 5) of a piezoelectric ceramic rectangular plate (piezoelectric vibrator) 11. At this time, a linear conductor of a flexible insulating sheet (FPC) is formed at a position where the linear conductor can be connected to the input / output electrode.
It was done by soldering. 53a and 53b are output electrodes, 54e to h are openings provided in the circuit board 14, and 56e to h are flexible insulating sheets (EPC) 17
The opening is provided in the opening.

By adopting the configuration of the seventh embodiment shown in FIG. 5, it is possible to form an inverter circuit having a dimension substantially equal to the width of a piezoelectric ceramic rectangular plate (piezoelectric vibrator).

At this time, the element size is 40 mm ×
Case size is 43mm x for 6mm x 1.5mm
Very compact, 7.5 mm x 2.5 mm. Also, since the flexible insulating sheet is taken out from only one direction of the case, mounting on the circuit board is very easy.

[0034]

As described above, if the piezoelectric transformer power supply of the present invention is used, the lead wires and the like need not be routed.
Since a flexible insulating sheet having a plurality of connection conductors on one surface allows an electric signal to be easily connected to an external circuit board from one surface of the piezoelectric vibrator, the working time is greatly reduced, and the case, Since the piezoelectric transformer, flexible insulating sheet and circuit board can be integrated, the reliability is sufficiently improved,
In addition, since the size, height, and cost can be significantly improved, the practical effect is extremely large.

[Brief description of the drawings]

FIGS. 1A and 1B show a piezoelectric transformer according to a first embodiment of the present invention, wherein FIG. 1A is an exploded perspective view, and FIG.
It is sectional drawing by the A 'line.

FIG. 2 is an exploded perspective view showing a piezoelectric transformer according to a third embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a piezoelectric transformer according to a fourth embodiment of the present invention.

FIG. 4 is an exploded perspective view showing a piezoelectric transformer according to a fifth embodiment of the present invention.

5A and 5B show a piezoelectric transformer according to a seventh embodiment of the present invention, wherein FIG. 5A is an exploded perspective view, and FIG.
It is sectional drawing by the B 'line.

FIGS. 6A and 6B are perspective views of first and second conventional piezoelectric transformers, which are shown in FIGS.

FIG. 7 is a perspective view showing a third conventional piezoelectric transformer using a flexible insulating sheet.

[Explanation of symbols]

 11 Piezoelectric ceramic rectangular plate (piezoelectric vibrator) 12a, 12b Input electrode 13a, 13b Output electrode 14 Circuit board 14e-h Opening 15 Case 15a-d External convex part 16a-d Linear conductor 16e-h Opening 17 Flexible Insulating sheet (FPC) 18 Circuit component 19 Land 24e-h Opening 25a-d External convex part 34e-h Opening 35a-d External convex part 36e-h Opening 44e-h Opening 46e-h Opening 53a, 53b Output electrode 54e-h opening 56e-h opening

Continuation of the front page (72) Inventor Yoshiaki Futa 6-7-1, Koriyama, Taishiro-ku, Sendai-shi, Miyagi Prefecture Tokin Co., Ltd.

Claims (7)

[Claims] 1. A piezoelectric transformer having at least one set of input electrodes for inputting power and at least one output electrode for extracting power is inserted into a case, and the piezoelectric transformer is inserted on a circuit board. In a piezoelectric transformer power supply in which a case and a circuit component capable of controlling and driving the piezoelectric transformer are mounted, the case has an externally formed convex portion that can be inserted into an opening of the circuit board, and has a point inside the piezoelectric transformer inside. After the function of supporting or fixing the vibration node in the shape of a line or a line is formed, the piezoelectric transformer is inserted into the case, and further, the piezoelectric transformer inserted into the case and the circuit board are disposed between the piezoelectric transformer and the circuit board. A flexible insulating sheet provided on one surface with a plurality of connection conductors connected to each of the input electrode and the output electrode is interposed, and the flexible insulating sheet is The input electrode and the output electrode and the connection conductor are electrically connected one to one on one surface of a vibrator rectangular plate of the piezoelectric transformer, And after inserting the convex part of the case into the opening of the flexible insulating sheet, it is inserted and fixed in the opening of the circuit board, and further, the circuit board and the connection conductor are electrically connected. A piezoelectric transformer power supply. 2. The piezoelectric transformer power supply according to claim 1, wherein an external projection of the case and an opening of the circuit board are fixed by bonding. 3. An external projection of the case is formed of metal, and a land is formed of metal foil around an opening of the circuit board into which the external projection is inserted. After inserting the part into the opening of the circuit board,
2. The piezoelectric transformer power supply according to claim 1, wherein the solder is fixed by melting the solder. 4. An outer convex portion of the case is formed of metal, and an opening of the flexible insulating sheet into which the outer convex portion is inserted and an opening of the circuit board are landed with metal foil around. 2. The piezoelectric transformer power supply according to claim 1, wherein the external transformer of the case is inserted into an opening of the circuit board, and then fixed by melting solder. 5. The land surrounding the opening of the flexible insulating sheet and the land surrounding the opening of the circuit board are electrically connected to each other. The piezoelectric transformer power supply according to claim 4. 6. The piezoelectric transformer has at least one pair of input electrodes for inputting electric power from a side surface of the vibrator rectangular plate and at least one output electrode for extracting electric power. The piezoelectric transformer power supply according to claim 1, 2, 3, 4, or 5. 7. The piezoelectric transformer has at least one set of input electrodes for inputting power from one surface of the vibrator rectangular plate and at least one output electrode for extracting power. Claims 1, 2, 3, 4
Or the piezoelectric transformer power supply according to 5.