JPH1012942A - Piezoelectric transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable piezoelectric transformer in which the size, the height and the cost can be reduced. SOLUTION: The piezoelectric transformer comprises a piezoelectric transformer element 2 including a rectangular piezoelectric oscillator plate 20, input electrodes 21, 22 and an output electrode 25, a cover 3 for supporting the piezoelectric transformer element 2, linear conductors 40-42 for connecting the input electrodes 21, 22 and the output electrode 25 electrically with a circuit board 8, and a flexible insulation sheet 4 for connecting the piezoelectric transformer element 2 with the circuit board 8. The flexible insulation sheet 4 has connecting parts 43-45 projecting closer to the piezoelectric transformer element 2 than the flexible insulation sheet 4 and abutting against one side of the piezoelectric transformer element 2. The linear conductors 40-42 are connected at the connecting parts 43-45 with the input electrodes 21, 22 and the output electrode 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transformer device using a piezoelectric transformer element, in particular, by extracting a power by using a flexible insulating sheet having a linear conductor and extracting power only from one outer surface. Another object of the present invention is to provide a piezoelectric transformer power supply having high reliability, small size and low profile.

[0002]

2. Description of the Related Art A piezoelectric transformer device is known as a device using a piezoelectric vibrator rectangular plate. At present, ceramics and lithium niobate single crystals are often used as vibrators for piezoelectric transformers.
As shown in the schematic diagrams of FIGS. 3A and 3B, input electrodes 21 and 22 for inputting electric power and an electrode for outputting electric power are respectively provided on the upper and lower surfaces and one side surface of the piezoelectric vibrator rectangular plate 20. An output electrode 25 is formed, and power input and output are directly soldered to electrodes 21, 22, and 25 formed on the surface of the piezoelectric vibrator rectangular plate 20, as shown in FIG. 3B, or through an elastic leaf spring-like conductor 14 in contact with the electrodes 21, 22, 25 as shown in FIG. 3B. Was.

Further, as shown in FIG. 4, even in the case of a piezoelectric transformer device using a flexible insulating sheet 4, power is taken out from a plurality of outer surfaces of a piezoelectric vibrator rectangular plate 20, so that reliability is improved. Poor properties and complicated structure.

Further, prior to the present application, a piezoelectric transformer element 2 as shown in FIG.
, A cover 3 and a flexible insulating sheet 4 have been filed, but the structure of this piezoelectric transformer device may cause some deterioration in characteristics when high performance and high efficiency are achieved. occured.

[0005]

In general, there is a strong demand for a piezoelectric transformer device having high reliability, miniaturization, low profile, and low cost.
There was a drawback that these requirements could not be sufficiently satisfied.

That is, as shown in FIG. 3, since the piezoelectric transformer element is connected to a circuit board by a lead wire or the like, the mounting area and man-hours are enormous even if the piezoelectric transformer device is reduced in size and height. Further, when trying to take out the leads only from the outer surface of the piezoelectric transformer element, the lead wires are complicated and it is difficult to achieve high reliability, small size and low height. Furthermore, with the structure of the conventional piezoelectric transformer device,
When a flexible insulating sheet is used to connect the piezoelectric transformer element to the circuit board, power is extracted from a plurality of outer surfaces, which complicates the structure, increases reliability, and does not require further reduction in height. It was possible. Further, there is a disadvantage that the flexible insulating sheet restrains the piezoelectric transformer element and deteriorates the characteristics. As described above, the conventional piezoelectric transformer has a drawback that it is very difficult to sufficiently satisfy the market requirements for downsizing, reduction in height, and cost reduction.

[0007]

According to the present invention, a piezoelectric vibrator rectangular plate, at least one set of input electrodes for inputting electric power provided on a predetermined portion of the piezoelectric vibrator rectangular plate,
A piezoelectric transformer element having at least one output electrode provided on the piezoelectric vibrator rectangular plate to extract power, a cover supporting the piezoelectric transformer element at a node of the vibration, the input electrode, A piezoelectric transformer device having a linear conductor that electrically connects the output electrode to a circuit board, and a flexible insulating sheet disposed between one surface of the piezoelectric transformer element and a mounting surface of the circuit board. In the above, the flexible insulating sheet has a connection portion, and the connection portion protrudes toward the piezoelectric transformer element from a portion of the flexible insulation sheet removed from one side of the piezoelectric transformer element. A piezoelectric transformer device is provided in which the linear conductor is connected to the input electrode and the output electrode at the connection portion.

Further, according to the present invention, there is provided a piezoelectric transformer device wherein the connection portion is formed in a substantially arc shape.

Further, according to the present invention, there is provided a piezoelectric transformer device wherein the connection portion is formed in a substantially corrugated shape.

[0010]

According to the piezoelectric transformer device of the present invention, the piezoelectric transformer element is connected to the circuit board via a flexible insulating sheet having a linear conductor. The flexible insulating sheet has a connection portion, which protrudes toward the piezoelectric transformer element and comes into contact with one surface of the piezoelectric transformer element. At this connection portion, the linear conductor of the flexible insulating sheet is connected to the input electrode and the output electrode of the piezoelectric transformer element, respectively. Therefore, since only the connection portion of the flexible insulating sheet is in contact with one surface of the piezoelectric transformer element, it is possible to connect the circuit board with only one surface of the piezoelectric transformer element without deteriorating the characteristics of the piezoelectric transformer. It becomes possible. As a result, the number of components and the mounting area can be reduced while ensuring sufficient reliability, and miniaturization, reduction in height, and reduction in cost can be achieved.

[0011]

FIG. 1 is an exploded perspective view of a piezoelectric transformer according to a first embodiment of the present invention. Referring to FIG. 1, the piezoelectric transformer 1 has a piezoelectric transformer element 2, a cover 3, and a flexible insulating sheet 4.

A plurality of input electrodes (input electrodes formed inside are not shown in the figure) inside and in the upper and lower surfaces of a half portion of the piezoelectric ceramic rectangular plate (piezoelectric vibrator rectangular plate) 20 in the longitudinal direction. The formed input electrodes are particularly referred to as “internal electrodes” 21 and 22. The input electrode 21 is shifted to one side in the width direction of the piezoelectric ceramic rectangular plate 20, and similarly, the input electrode 22 is shifted to the opposite side to the input electrode 21. Similarly, the internal electrodes are alternately shifted. On both sides of the piezoelectric ceramic rectangular plate 20,
One set of external electrodes 23 and 24 is formed. These external electrodes 23 and 24 are electrically connected to the above-mentioned input electrodes every other layer, respectively.
Reference numerals 24 each constitute a part of an input electrode. The portions where the external electrodes 23 and 24 are formed correspond to the nodes of vibration of the piezoelectric ceramic rectangular plate 20. Further, an output electrode 25 is formed on one end surface of the piezoelectric ceramic rectangular plate 20 in the longitudinal direction. Here, the piezoelectric ceramic rectangular plate 2
0 is 40 mm × 6 mm × 1.5 mm, and P
The internal electrodes are formed by integrally sintering Ag / Pd using a ZT-based ceramic.
2. The external electrodes 23 and 24 and the output electrode 25 are made of Ag.
Is formed by baking. The above piezoelectric ceramic rectangular plate 20, input electrode, and external electrodes 23 and 2
4, and the output electrode 25 constitute the piezoelectric transformer element 2 described above.

The cover 3 accommodates the piezoelectric transformer element 2 and supports and fixes the piezoelectric transformer element 2 at a vibration node thereof. The cover 3 is formed by injection molding a resin. . 30, 31, 32, 3
Reference numeral 3 denotes an outer convex portion of the cover 3.

The flexible insulating sheet 4 is disposed between the lower surface of the piezoelectric transformer element 2 and the mounting surface of the circuit board 8, and connects the piezoelectric transformer element 2 to the circuit board 8. The flexible insulating sheet 4 includes three insulated conductor patterns (linear conductors) 40, 41, 42, 3
Four connections 43,44,45 and four openings 46,
47, 48, and 49. The portion of the flexible insulating sheet 4 other than the vicinity of the vibration node of the piezoelectric transformer element 2 forms an opening 50. Connection parts 43, 44, 45
Is curved in the thickness direction. This flexible insulating sheet 4
Consists of FPC. One ends of the conductor patterns 40, 41, 42 are connected one-to-one with the external electrodes 23, 24 (part of the input electrode) and the output electrode 25 of the piezoelectric transformer element 2 on the connection portions 43, 44, 45, respectively. And are electrically connected.

The above-mentioned outer projections 30, 31, 3 of the cover 3
2 and 33 are the openings 46 of the flexible insulating sheet 4,
47, 48, and 49, and further inserted and fixed in openings 80, 81, 82, and 83 formed in the circuit board 8. Thus, the piezoelectric transformer device 1 was formed on the circuit board 8, and the other ends of the conductor patterns 40, 41, 42 were connected to the pads 84, 85, 86 of the circuit board 8.

FIG. 2 is an exploded perspective view of a piezoelectric transformer device according to a second embodiment of the present invention. The piezoelectric transformer device 1 of the present embodiment is the same as the piezoelectric transformer device 1 of the first embodiment.
Since the configuration is substantially the same as that of the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof will be omitted.

In the case of the piezoelectric transformer device 1 of the present embodiment,
The shape of the contact portions 43, 44, 45 of the flexible insulating sheet 4 is different from that of the first embodiment. In the case of the present embodiment, the contact portions 43, 44, 45 are formed in a substantially corrugated plate shape. The piezoelectric transformer device 1 of the present embodiment has substantially the same characteristics as the piezoelectric transformer device 1 of the first embodiment.

The piezoelectric transformer devices according to the first and second embodiments, a piezoelectric transformer device using a general lead wire, and a piezoelectric transformer device having a conventional flexible insulating sheet (FPC) are described. Table 1 shows the experimental results when the characteristics were compared between the above. At this time, each piezoelectric transformer device is a monolithic product (10 layers), and the load is φ2 mm ×
A 200 mm cold cathode tube was used. As shown in Table 1, even when the flexible insulating sheet (FPC) is used, the same characteristics as those of the conventional lead extraction are obtained. Table 2 shows the aging results, but no deterioration of the characteristics can be confirmed after 1000 hours.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

As described above, in the piezoelectric transformer device of the present invention, it is not necessary to route the lead wires and the like, and the one side of the piezoelectric transformer element can be easily and electrically connected to the circuit board by the flexible insulating sheet. Therefore, while maintaining the desired characteristics, the working time is significantly reduced,
Since the piezoelectric transformer element and the flexible insulating sheet can be easily integrated with the circuit board, the reliability can be sufficiently increased, and the size and height can be greatly reduced. The device has a very large practical effect.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a piezoelectric transformer device according to a first embodiment of the present invention.

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

FIG. 3 shows a conventional general piezoelectric transformer device;
(A) is a perspective view of a piezoelectric transformer device using a lead wire,
(B) is a perspective view of a piezoelectric transformer device using a leaf spring-like conductor.

FIG. 4 is a perspective view of an example of a conventional piezoelectric transformer device using a flexible insulating sheet.

FIG. 5 is a perspective view of another conventional piezoelectric transformer device using a flexible insulating sheet.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 piezoelectric transformer device 2 piezoelectric transformer element 3 cover 4 flexible insulating sheet 20 piezoelectric ceramic rectangular plate (piezoelectric transducer rectangular plate) 21 input electrode 22 input electrode 23 external electrode 24 external electrode 25 output electrode 40 conductor pattern ( (Linear conductor) 41 Conductor pattern (Linear conductor) 42 Conductor pattern (Linear conductor) 43 Contact part 44 Contact part 45 Contact part

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

Claims (3)

[Claims] 1. A piezoelectric vibrator rectangular plate, at least one set of input electrodes provided on a predetermined portion of the piezoelectric vibrator rectangular plate for inputting power, and a piezoelectric vibrator rectangular plate for extracting power. A piezoelectric transformer element having at least one output electrode provided, a cover supporting the piezoelectric transformer element at a node of the vibration, and electrically connecting the input electrode and the output electrode to a circuit board And a flexible insulating sheet disposed between one surface of the piezoelectric transformer element and a mounting surface of the circuit board, wherein the flexible insulating sheet includes a connecting portion. The connecting portion is configured to protrude toward the piezoelectric transformer element from the removed portion of the flexible insulating sheet and abut on one surface of the piezoelectric transformer element. part Wherein the linear conductor is connected to the input electrode and the output electrode. 2. The piezoelectric transformer device according to claim 1, wherein the connection portion is formed in a substantially arc shape. 3. The piezoelectric transformer device according to claim 1, wherein the connecting portion is formed in a substantially corrugated shape.