JPH1079534A - Piezoelectric transformer and power supply for piezoelectric transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide inexpensive piezoelectric transformer and power supply for piezoelectric transformer which can satisfy high reliability, even though they are miniaturized as in size and height. SOLUTION: At least one set of input electrodes 12a and 12b for inputting electric power and at least one electrode for outputting output electrode are provided to a piezoelectric transformer member. The piezoelectric transformer member is arranged on a substrate 19 with a flexible insulation plate interposed, and they are made integral through shrinkage of a thermal shrinkage tube 18 and are fixed thereafter. The substrate is provided with a notched part slightly wider than the width of a sheet at the position corresponding to the piezoelectric transformer member. The heat shrinkable tubing is attached to a position, corresponding to the notched part of the substrate.

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 a piezoelectric transformer power supply.

[0002]

2. Description of the Related Art Conventionally, there has been known a piezoelectric transformer using a piezoelectric transformer vibrator formed of a piezoelectric vibrator rectangular plate.

Referring to FIG. 7, this type of piezoelectric transformer 1
Is applied as a DC-DC converter or an inverter, and is connected to an electronic power supply circuit including a drive circuit 2, a control circuit 3, and a feedback circuit 4 to constitute a piezoelectric transformer power supply. The piezoelectric transformer power supply shown here is a piezoelectric transformer type inverter in which Vin receives a DC (direct current) input and Vout generates an AC (alternating current) output.

At present, ceramic or lithium niobate single crystal is often used as a vibrator for a piezoelectric transformer, and the general structure is as shown in the schematic diagram of FIG. Alternatively, input electrodes 12a and 12b capable of inputting and outputting power and an output electrode 13 are formed on the side surfaces to form a piezoelectric transformer member, and power is taken out by connecting lead wires 12c, 12d and 13c to the electrodes formed on the piezoelectric transformer member. 8B is directly soldered or taken out with a spring-shaped conductor 44 as shown in FIG. 8B.

Further, in the piezoelectric transformer and the piezoelectric transformer power supply shown in FIG. 9, a piezoelectric transformer member comprising a piezoelectric ceramic rectangular plate 11 provided with input electrodes 12a, 12b and an output electrode 13 is connected to linear conductors 16a, 16b, It is fixed to the circuit board 14 via a flexible insulating plate 17 provided with 16c, and a case 15 is covered to insulate high voltage (see Japanese Patent Application No. 8-155825).

In order to achieve a lower profile and lower cost,
It has also been proposed to use heat-shrinkable tubes 58a and 58b as insulating sheets instead of the case as shown in FIG. 10 (see Japanese Patent Application No. 8-162242).

[0007]

In general, piezoelectric transformers are required to have high reliability and to be very compact, low-profile, and low in cost. There is a drawback that it is difficult to achieve a balance between compactness, low profile, and low cost.

More specifically, as shown in FIG. 10, when the piezoelectric transformer member and the substrate are integrated and fixed using an insulating sheet, the thickness of the case is smaller than that when the piezoelectric transformer member is fixed using a case. Only a very low profile can be achieved,
In terms of reliability, especially in the case where the substrate is susceptible to impact in the longitudinal direction of the substrate, and when higher reliability is required, such as in a vehicle, there is a defect that the required conditions cannot be satisfied.

As described above, the conventional piezoelectric transformer and the piezoelectric transformer power supply have a drawback that it is very difficult to sufficiently satisfy the market requirements of reliability, small size, low profile, and low cost.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a piezoelectric transformer and a low cost piezoelectric transformer and a piezoelectric transformer power supply which can sufficiently satisfy high reliability even if the size and height are reduced.

[0011]

According to the present invention, there is provided a piezoelectric transformer member having at least one set of input electrodes for inputting power and at least one output electrode for extracting power, and the piezoelectric transformer. A piezoelectric member comprising: a substrate directly disposed with members; and an insulating sheet, wherein the substrate has at least one notch at a position corresponding to the piezoelectric transformer member, which is slightly wider than the width of the sheet. And a piezoelectric transformer, wherein the substrate is integrated and fixed by the sheet at a position corresponding to the notch.

Further, according to the present invention, a piezoelectric transformer member having at least one set of input electrodes for inputting electric power and at least one output electrode for extracting electric power; Wherein the substrate has at least one notch slightly wider than the width of the sheet at a position corresponding to the piezoelectric transformer member. A piezoelectric transformer is obtained, wherein the transformer member, the substrate, and the insulating plate are integrated and fixed by the sheet at a position corresponding to the cutout.

According to the present invention, a piezoelectric transformer having at least one pair of input electrodes for inputting power and at least one output electrode for extracting power, and the piezoelectric transformer is directly disposed and A circuit board for driving and controlling, and an insulating sheet, wherein the circuit board has at least one notch at a position corresponding to the piezoelectric transformer, which is slightly wider than the width of the sheet; A piezoelectric transformer power supply is obtained, wherein the circuit board is integrated and fixed by the sheet at a position corresponding to the notch.

According to the invention, there is provided a piezoelectric transformer having at least one set of input electrodes for inputting power and at least one output electrode for extracting power, and a flexible insulating plate comprising the piezoelectric transformer. And a circuit board for driving and controlling the circuit board, and an insulating sheet, wherein the circuit board has at least one cutout slightly wider than the width of the sheet at a position corresponding to the piezoelectric transformer. Further, a piezoelectric transformer power supply is obtained, wherein the piezoelectric transformer, the circuit board, and the insulating plate are integrated and fixed by the sheet at a position corresponding to the cutout portion.

[0015]

When the piezoelectric transformer and the piezoelectric transformer power supply of the present invention are used, a notch portion is provided on a substrate or a circuit board to improve impact resistance in the longitudinal direction, sufficiently secure high reliability, and at the same time reduce the height. In addition, downsizing and cost reduction can be achieved.

[0016]

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

[0017]

FIG. 1 is a perspective view showing a piezoelectric transformer according to a first embodiment of the present invention. The piezoelectric transformer shown in FIG. 1 includes a piezoelectric transformer member. The piezoelectric transformer member has a plurality of internal electrodes inside a piezoelectric ceramic rectangular plate 11, and a set, ie, a pair of external electrodes, that is, a pair of external electrodes, ie, input electrodes 12a, which are alternately electrically connected to the internal electrodes.
12b is formed on both long side surfaces of the piezoelectric ceramic rectangular plate 11, and an output electrode 13 is formed on the short side end surface of the piezoelectric ceramic rectangular plate 11. Here, the dimensions of the piezoelectric ceramic rectangular plate 11 are 40 mm × 6 mm × 1.5 mm, and are made using a PZT-based lamic. The internal electrodes are formed by Ag / Pb integral sintering, and the input electrodes 12a, 12b and the output
g.

Further, leads 121a, 12 for pulling out
1b and 131 are connected to the input electrodes 12a and 12b and the output electrode 13, respectively, and then a plurality of notches 2 are formed at both ends in the width direction.
The piezoelectric transformer member is disposed directly on the substrate 19 on which the 0a and 20b are formed so as to correspond to the notches 20a and 20b. Thereafter, this is inserted into the heat-shrinkable tube 18 constituting an insulating sheet, and the heat-shrinkable tube 18 is made to correspond to the notches 20a and 20b. The length of the heat-shrinkable tube 18 is slightly shorter than the width of the notches 20a and 20b. That is, the heat-shrinkable tube 18 constitutes an insulating sheet, and the widths of the notches 20a and 20b of the substrate 19 are made slightly wider than the width of the sheet.

Next, the heat-shrinkable tube 18 is shrunk by heating, thereby fixing the whole so as to be integrated. Here, the heat-shrinkable tube 18 may be shrunk by applying heat of about 100 ° C. with a dryer.

FIG. 2 is a perspective view showing a piezoelectric transformer according to a second embodiment of the present invention. The piezoelectric transformer member of the piezoelectric transformer shown in FIG. 2 has a plurality of internal electrodes inside a piezoelectric ceramic rectangular plate 11, and a pair of external electrodes, ie, input electrodes, which are alternately and electrically connected to the internal electrodes. 12a and 12b are formed on both side surfaces of a piezoelectric ceramic rectangular plate 11, and output electrodes 13 are formed on end surfaces of the piezoelectric ceramic rectangular plate 11. Here, the dimensions of the piezoelectric ceramic rectangular plate 11 are 40 mm × 6 mm × 1.5 mm, and are made using a PZT-based lamic. The internal electrodes are formed by Ag / Pb integral sintering, and the input electrodes 12a, 12b and the output
g.

Further, a flexible insulating plate (FPC) 17 having three linear conductors 16a, 16b and 16c, each of which is insulated, is formed therein, and the input electrodes 12a and 12b and the output electrodes of the piezoelectric transformer member are formed. After the electrodes 13 are electrically connected to the linear conductors 16a, 16b, 16c of the insulating plate 17 in one-to-one correspondence, a plurality of notches 20a,
This piezoelectric transformer member is disposed on the substrate 19 on which the 20b is formed, with the insulating plate 17 interposed therebetween so as to correspond to the notches 20a and 20b. Thereafter, this is inserted into the heat-shrinkable tube 18 constituting an insulating sheet, and the heat-shrinkable tube 18 is made to correspond to the notches 20a and 20b. Also in this case, the width of the notches 20a and 20b of the substrate 19 is made slightly larger than the width of the sheet, that is, the length of the heat-shrinkable tube 18.

Next, the heat-shrinkable tube 18 is shrunk by heating to cover the piezoelectric transformer member and the insulating plate 17, thereby fixing the whole so as to be integrated.

FIG. 3 is a perspective view showing a piezoelectric transformer power supply according to a third embodiment of the present invention. The piezoelectric transformer power supply shown in FIG. 3 includes a piezoelectric transformer member. The piezoelectric transformer member has a plurality of internal electrodes inside a piezoelectric ceramic rectangular plate 11, and a pair of external electrodes, that is, input electrodes 12a, which are alternately electrically connected to the internal electrodes.
12b are formed on both sides of the piezoelectric ceramic rectangular plate 11,
Further, an output electrode 1 is provided on the end face of the piezoelectric ceramic rectangular plate 11.
3 is formed. Here, the dimensions of the piezoelectric ceramic rectangular plate 11 are 40 mm × 6 mm × 1.5 mm.
It is made using ZT-based lamic. The internal electrode is Ag
/ Pb is formed by integral sintering, and the input electrodes 12a, 12b and the output electrode 13, which are external electrodes, are formed by baking Ag.

The input electrodes 12a and 12b and the output electrode 13 are connected to a plurality of cutouts 22 by using lead wires.
a and 22b are connected to the electrodes of the circuit board 21. Finally, the piezoelectric transformers 22a and 22b and the circuit board 21 are inserted into the heat-shrinkable tube 18 forming an insulating sheet so as to correspond to the cutouts 22a and 22b.
8 is heated to shrink, and the piezoelectric transformer member and the circuit board 21 are fixed so as to be integrated. Here, the overall thickness of the piezoelectric transformer power supply is 2.5 mm, which is 1 /
2 thickness. In this case, the notch 22 of the circuit board 21
The width of a, 22b is made slightly larger than the width of the sheet, that is, the length of the heat-shrinkable tube 18.

FIG. 4 is a perspective view showing a piezoelectric transformer power supply according to a fourth embodiment of the present invention. The piezoelectric transformer member of the piezoelectric transformer power supply shown in FIG.
A pair of external electrodes, that is, input electrodes 12a and 12b, each having a plurality of internal electrodes therein and alternately electrically connected to the internal electrodes, are formed on both side surfaces of the piezoelectric ceramic rectangular plate 11, Further, an output electrode 13 is formed on an end face of the piezoelectric ceramic rectangular plate 11. Here, the dimensions of the piezoelectric ceramic rectangular plate 11 are 40 mm × 6 mm × 1.
It is 5 mm and is made using a PZT-based lamic. The internal electrodes are formed by integral sintering of Ag / Pb, and the input electrodes 12a and 12b and the output electrode 13 are formed by baking Ag.

Further, a flexible insulating plate (FPC) 17 having three linear conductors 16a, 16b and 16c each of which are insulated is formed inside, and the input electrodes 12a and 12b and the output electrodes of the piezoelectric transformer member are formed. The electrodes 13 are electrically connected to the linear conductors 16a, 16b, 16c of the insulating plate 17 in one-to-one correspondence, and a plurality of notches 22 are provided at both ends in the width direction.
a, 22b were connected to the electrodes of the circuit board 21. Finally, this is inserted into the heat-shrinkable tube 18 constituting an insulating sheet so as to correspond to the notches 22a and 22b, and the heat-shrinkable tube 18 is heated and shrunk, so that the piezoelectric transformer member and the circuit board 21 are integrated. Fixed so that Also in this case, the width of the notches 22a and 22b of the circuit board 21 is made slightly larger than the width of the sheet, that is, the length of the heat-shrinkable tube 18.

In any of the configurations shown in FIGS. 1 to 4, it is possible to cover and fix the vicinity of the vibration node of the piezoelectric transformer with heat-shrinkable tubes 58a and 58b as in the modified embodiment shown in FIG. It is. Since the piezoelectric transformer used here is driven in the one-wavelength mode, the vibration nodes each have a quarter size from both ends in the longitudinal direction of the piezoelectric transformer, and are present at two locations. Therefore, a plurality of notches 22a, 22b, 22c, 22d correspond to these vibration nodes.
Should be provided.

Further, as in the modified embodiment shown in FIG.
One half of the length of the piezoelectric transformer vibrator in the length direction is used as an input electrode and polarized in the thickness direction.
In the case of a configuration in which the output electrode is formed in a linear shape having a length of / 4, and the region is divided into two and polarized in the opposite direction, the output electrode from which the high voltage is output is flexible by a heat-shrinkable tube at the vibration node. High reliability because it can be fixed and integrated with a flexible insulating plate or circuit board.

Table 2 shows the characteristics of typical examples of the piezoelectric transformer power supply. The piezoelectric transformer used for the evaluation was an integrally laminated product (10 layers), and a cold cathode tube of φ2 mm × 200 mm was used as a load. Table 1 shows the results of the impact test of the conventional circuit board having no notch and the circuit board having the notch of the present invention. It can be seen that the configuration of the present invention improves the impact resistance in the length direction of the circuit board. Table 2
Shows the aging results, but no deterioration of the characteristics can be confirmed after 1000 hours.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

As described above, if the piezoelectric transformer and the piezoelectric transformer power supply of the present invention are used, the insulating sheet for the cover can be stably fixed by providing the cutout portion on the substrate or the circuit board, so that the lengthwise direction can be improved. The practical effect is very large because the impact resistance can be improved, the height can be easily reduced while ensuring sufficient reliability, and the production cost can be reduced.

[Brief description of the drawings]

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

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

FIG. 3 is a perspective view showing a piezoelectric transformer power supply according to a third embodiment of the present invention.

FIG. 4 is a perspective view showing a piezoelectric transformer power supply according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view showing a piezoelectric transformer power supply according to a modified example of the present invention.

FIG. 6 is a perspective view showing a piezoelectric transformer power supply according to another modification of the present invention.

FIG. 7 is a block diagram showing a configuration of a general piezoelectric transformer power supply.

FIG. 8 is a perspective view showing a conventional piezoelectric transformer.

FIG. 9 is an exploded perspective view of an example of a conventional piezoelectric transformer power supply.

FIG. 10 is a perspective view of another example of a conventional piezoelectric transformer power supply.

[Explanation of symbols]

Reference Signs List 11 piezoelectric ceramic rectangular plate 12a, 12b input electrode 13, 63, 64, 65 output electrode 21 circuit board 19 substrate 15 case 16a-c linear conductor 17 flexible insulating plate (FPC) 18 heat-shrinkable tube 58a , 58b Heat-shrinkable tubes 121a, 121b, 131 Lead wires 20a, 20b, 22a, 22b, 22c, 22d
Notch

Claims (4)

[Claims] 1. A piezoelectric transformer member having at least one set of input electrodes for inputting power and at least one output electrode for extracting power, a substrate on which the piezoelectric transformer member is directly disposed, and an insulating member. And the substrate has at least one cutout portion slightly wider than the width of the sheet at a position corresponding to the piezoelectric transformer member, and the piezoelectric transformer member and the substrate correspond to the cutout portion. A piezoelectric transformer, wherein the piezoelectric transformer is integrated and fixed by the sheet at a position. 2. A piezoelectric transformer member having at least one set of input electrodes for inputting electric power and at least one output electrode for extracting electric power, and the piezoelectric transformer member is connected via a flexible insulating plate. A substrate, and an insulating sheet, wherein the substrate has at least one cutout portion slightly wider than the width of the sheet at a position corresponding to the piezoelectric transformer member. A piezoelectric transformer, wherein the insulating plate is integrated and fixed by the sheet at a position corresponding to the cutout portion. 3. A piezoelectric transformer having at least one set of input electrodes for inputting power and at least one output electrode for extracting power, and a circuit for directly arranging the piezoelectric transformer and driving and controlling the same. A circuit board including an insulating sheet, the circuit board having at least one cutout portion slightly wider than the width of the sheet at a position corresponding to the piezoelectric transformer; A piezoelectric transformer power supply, wherein the piezoelectric transformer power supply is integrated and fixed by the sheet at a position corresponding to the portion. 4. A piezoelectric transformer having at least one pair of input electrodes for inputting electric power and at least one output electrode for extracting electric power, and the piezoelectric transformer is arranged via a flexible insulating plate. A circuit board for driving and controlling the piezoelectric transformer; and an insulating sheet, wherein the circuit board has at least one cutout portion slightly wider than the width of the sheet at a position corresponding to the piezoelectric transformer. A piezoelectric transformer power supply, wherein the circuit board and the insulating plate are integrated and fixed by the sheet at a position corresponding to the cutout portion.