JPH09116250A - Piezoelectric transformer retaining member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain height reduction of a piezoelectric transformer and prevent the deterioration of vibrator characteristics, by a method wherein retainers which serve as plate spring type electrodes are so arranged at the positions corresponding to the positions of the nodes of vibration of a piezoelectric transformer inside a frame type holder that terminals for board mounting protrude to the outside of the frame type holder. SOLUTION: A piezoelectric transformer retaining member 1 is constituted of a frame type holder 2 and two pairs of retainers 3. The frame type holder 2 is a size lager than a piezoelectric transformer 11, and recessed parts 20 are formed inside the frame type holder 2 for arranging the retainers 3. The recessed parts 20 are formed at the positions corresponding to nodes of vibration of the piezoelectric transformer 11. The retainers 3 which serve as plate spring type electrode metal fixtures are arranged so as to protrude from the inside of the frame type holder 2 to the piezoelectric transformer 11 side. When this retaining member is used, the piezoelectric transformer 11 is only engaged with the frame type holder 2, and input and output electrodes 100, 101, 15, 16 of the piezoelectric transformer 11 are brought into contact with the retainers (plate spring type electrode metal fixtures) 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage DC / DC converter used for toner charging of a copying machine, a DC / A used for a liquid crystal backlight inverter, and the like.
It belongs to a piezoelectric transformer support device that supports a piezoelectric transformer that uses mechanical vibration of a piezoelectric vibrator used in a C inverter.

[0002]

2. Description of the Related Art FIG. 4 shows a piezoelectric ceramic rectangular plate vibrating in a one-wavelength resonance mode in a longitudinal direction, and a position at a length of a quarter of the piezoelectric ceramic rectangular plate from both longitudinal end faces of the piezoelectric ceramic rectangular plate. FIG. 4 is a perspective view showing an example of the structure of a piezoelectric transformer in which a vibration node is present.

In FIG. 4 (a), the piezoelectric ceramic rectangular plate 12 is provided on substantially the entire area of one half of the length of the piezoelectric ceramic rectangular plate 12 from one end face in the longitudinal direction of the piezoelectric ceramic rectangular plate 12. First counter electrodes 13 and 14 facing each other in the thickness direction are formed, and second counter electrodes 15 and 16 facing each other in the width direction of the piezoelectric ceramic rectangular plate 12 are formed on both side surfaces of the remaining half area. In the width direction of the piezoelectric ceramic rectangular plate 12, the two side surfaces of the piezoelectric ceramic rectangular plate 12 separated from the one end surface in the longitudinal direction of the piezoelectric ceramic rectangular plate 12 by about a quarter of the length of the piezoelectric ceramic rectangular plate 12 are formed. Third counter electrodes 17 and 18 are formed.

One electrode 17 of the third counter electrode and one electrode 13 of the first counter electrode shown in FIG. 4A, and the other electrode 18 of the third counter electrode and the first counter electrode. The other electrode 14 is electrically connected to drive electrodes 100 and 101, respectively, as shown in FIG. Drive electrodes 100, 101 and second counter electrode 15,
16 are lead wires 102, 103, 104,
105 is soldered.

The piezoelectric ceramic rectangular plate 12 shown in FIG. 4 (b) is polarized in its thickness direction by using the drive electrodes 100 and 101 in a region of about ½ of its length, and the remaining two halves. In the area (1), the second counter electrodes 15 and 16 are used for polarization in the width direction. This polarization direction is indicated by an arrow.

In FIG. 4B, the drive electrodes 100, 1
When a voltage having a frequency substantially equal to the resonance frequency of the one-wavelength resonance mode of the piezoelectric ceramic rectangular plate 12 is applied to 01, the piezoelectric ceramic rectangular plate 12 vibrates in the longitudinal direction. At this time, a high voltage output is generated between the second opposing electrodes 15-16 by the piezoelectric lateral effect. In this way, the piezoelectric transformer 1
1 can be configured.

5A and 5B are explanatory views of the operation principle of the piezoelectric transformer. FIG. 5A is a side view of the piezoelectric transformer, and FIG. 5B is a case where the piezoelectric ceramic rectangular plate vibrates in a one-wavelength resonance mode of longitudinal vibration. (C) shows the strain distribution at that time. In FIG. 5A, the drive electrode 10
When a voltage having a frequency equal to the resonance frequency of the one-wavelength resonance mode of longitudinal vibration of the piezoelectric ceramic rectangular plate 12 is applied between the drive electrodes 100-101 with 0 and 101 as the primary side, the piezoelectric ceramic rectangular plate 12 is 5 (b) and FIG. 5 (c), the second counter electrode 15-1 vibrates as shown in FIG.
A high voltage is generated between 6 by the piezoelectric effect. FIG.
As shown in the displacement distribution diagram of (b), when the piezoelectric ceramic rectangular plate 12 is vibrating in the one-wavelength resonance mode of longitudinal vibration, the nodes of vibration are from both end faces in the longitudinal direction of the piezoelectric ceramic rectangular plate 12. Piezoelectric ceramic rectangular plate 1
The piezoelectric transformer 1 is located on a straight line parallel to the end face in the longitudinal direction of the piezoelectric ceramic rectangular plate 12 and passes through the positions 106 and 107 which are ¼ of the length of the piezoelectric transformer 1 at any position on these straight lines.
It is possible to support 1.

FIG. 6 shows an essential part of an example of a conventional piezoelectric transformer supporting device, (a) is a perspective view of the supporting member, and (b) is a perspective view showing a mounting state of the supporting member shown in (a) to the piezoelectric transformer. It is a figure. As shown in FIG. 6A, the supporting member 6 in the conventional piezoelectric transformer supporting device is formed in a U shape by using a soft rubber material.
As shown in FIG. 6 (b), the portions near the vibration nodes of the piezoelectric transformer are independently sandwiched in the thickness direction of the piezoelectric transformer 11 and fixed with a silicone adhesive or the like.

[0009]

There is a tendency for downsizing and thinning of devices and devices using a high-voltage DC / DC converter and an inverter for a liquid crystal backlight.
C / DC converters and liquid crystal backlight inverters are also required to be smaller and have a lower profile.

However, in the conventional supporting structure, four supporting members are required for one piezoelectric transformer, and each supporting member has to be fixed to the piezoelectric transformer, and the supporting members need to be fixed when mounted on the circuit board. After mounting the fixed piezoelectric transformer in the protective package, the protective package must be fixed to the circuit board, and the lead wires must be directly connected to the circuit board, which is extremely inconvenient in workability and includes the support. Moreover, since the total thickness of the piezoelectric transformer is limited by the height of the support, it is difficult to reduce the height.

Further, there is a problem in reliability such as disconnection due to excessive pulling of the lead wire at the time of connecting the lead wire or short circuit between the lead wire and the circuit board due to slack of the lead wire caused by insufficient pulling.

Further, originally, the support must be fixed at the position of the vibration node of the piezoelectric transformer, but since the lead wire is soldered at the position of the vibration node of the piezoelectric transformer, the conventional method is used. In the piezoelectric transformer support device, the support tool has to be fixed while being displaced from the vibration node of the piezoelectric transformer, which causes deterioration of the vibrator characteristics.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the conventional piezoelectric transformer supporting device, to make the height of the piezoelectric transformer low, and to improve the reliability of the piezoelectric transformer and the workability of mounting the piezoelectric transformer. It is an object of the present invention to provide a piezoelectric transformer supporting device capable of improving the vibration resistance and preventing the deterioration of the vibrator characteristics.

[0014]

According to the present invention, in a piezoelectric transformer supporting device for supporting a piezoelectric transformer having electrodes on the side surface of a piezoelectric ceramic rectangular plate, a frame-shaped holder slightly larger than the piezoelectric transformer is provided. A plurality of pairs of supporting members arranged in the frame-shaped holder and supporting the piezoelectric transformer at the nodes of vibration thereof, the supporting members being made of a material having elasticity and conductivity. The piezoelectric transformer is supported so as to be sandwiched in the width direction thereof, and is in electrical contact with the electrodes, and further has a board mounting terminal projecting to the outside of the frame-shaped holder. A piezoelectric transformer support device is obtained.

Further, according to the present invention, there is provided a piezoelectric transformer supporting device characterized in that an insulating sheet is adhered to the bottom surface of the frame-shaped holder.

Further, according to the present invention, there is obtained a piezoelectric transformer supporting device characterized in that flexible silicone is injected into a gap between the piezoelectric transformer and the frame-shaped holder.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a piezoelectric transformer supporting device according to a first embodiment of the present invention.

Referring to FIG. 1, the piezoelectric transformer supporting device 1 of this embodiment comprises a frame-shaped holder 2 and two pairs of supporting members 3. The frame-shaped holder 2 is slightly larger than the piezoelectric transformer 11, and a recess 20 for arranging the support 3 is formed inside thereof. The recess 20 is formed at a position corresponding to a node of vibration of the piezoelectric transformer 11.
Further, at one end of the concave portion 20, a groove 2 for guiding a board mounting terminal 30 of the support 3 described later to the outside of the frame-shaped holder 2.
1 is formed. The support tool 3 is made of a material having elasticity and conductivity, and has a substantially arcuate planar shape. At one end of each support 3, the board mounting terminal 3 is provided.
0 is connected. The support 3 is arranged in the recess 20, and the board mounting terminal 30 is provided in the groove 21 of the frame-shaped holder 2.
Through to the outside of the frame-shaped holder 2. As described above, the support tools 3 arranged in the recess 20 of the frame-shaped holder 2 are paired with each other (arranged along the width direction of the piezoelectric transformer 11) and sandwich the piezoelectric transformer 11 in the width direction. The electrodes 100, 101, 15, which are elastically supported so as to extend to the side surface of the piezoelectric transformer 11,
16 are respectively contacted and electrically connected to these electrodes. In this way, the support tool 3 also serves as a plate spring-shaped electrode fitting.

As described above, since the supporting member 3 also serving as the plate spring electrode fitting is arranged so as to project from the inside of the frame-shaped holder 2 to the piezoelectric transformer 11 side, the piezoelectric transformer 11 is used at the time of use. By simply fitting the above into the frame-shaped holder 2, the input / output electrodes 100, 101,
The support members (plate spring electrode metal fittings) 2 and 15 and 16 contact each other. Therefore, the board mounting terminals 30 provided on the support 2
Just solder the circuit board 8 to the piezoelectric transformer 11
Is fixed to the circuit board 8 and each input / output terminal 100, 101,
Since the electrical connection between 15 and 16 and the circuit board 8 is possible, the workability is improved, and the lead wire is not required, so that the conventional problem of short circuit between the lead wire and the circuit board is solved. And reliability is improved.

Further, since the support of the piezoelectric transformer 11 by the support 3 is the support in the width direction of the piezoelectric transformer 11, the total thickness of the support including the support 3 is thinner than the conventional one, and the piezoelectric transformer 11 has a low profile. In addition to being possible to
Since the vibration node portion of the piezoelectric transformer 11 is elastically supported by the support tool 2, it is possible to prevent the characteristic deterioration of the vibrator due to the support.

FIG. 2 is a schematic configuration diagram of a piezoelectric transformer support device according to a second embodiment of the present invention. Referring to FIG.
Since this embodiment has substantially the same configuration as the first embodiment,
The same reference numerals as those of the first embodiment are attached to the portions having the same configurations, the description thereof is omitted, and only the portions having the different configurations will be described. In the case of this embodiment, the insulating sheet 4 is bonded to the bottom surface (side surface of the circuit board) of the frame-shaped holder 2. With the insulating sheet 4, the piezoelectric transformer 11 and the circuit board 8
If the insulating sheet 4 is made of a material having a smooth surface such as a Teflon sheet, the insulating sheet 4 has a more reliable insulating property. It is possible to prevent characteristic deterioration due to.

FIG. 3 is a schematic configuration diagram of a piezoelectric transformer support device according to a third embodiment of the present invention. Referring to FIG.
Since the present embodiment has substantially the same configuration as the first and second embodiments, parts having the same configurations are denoted by the same reference numerals as those of the first and second embodiments, and the description thereof will be omitted. Only different parts will be described. In the case of this embodiment,
Flexible silicone 5 is injected into a gap between the piezoelectric transformer 11 and the frame-shaped holder 2. Thus, the impact resistance is improved by injecting the flexible silicone 5.

[0024]

As described above, the piezoelectric transformer supporting apparatus according to the present invention is mounted on the board at a position corresponding to the vibration node of the piezoelectric transformer inside the frame-shaped holder which is slightly larger than the piezoelectric transformer. Since the structure is such that the board mounting terminal has a support terminal that also functions as a plate spring-like electrode fitting so that the board mounting terminal projects to the outside of the frame-shaped holder, you can simply fit the piezoelectric transformer into the frame-shaped holder. A support that also serves as a plate spring electrode fitting and the input / output electrodes of the piezoelectric transformer are electrically connected. Therefore, it is possible to fix the piezoelectric transformer to the circuit board and electrically connect each input / output terminal to the circuit board by simply soldering the board mounting terminals provided on the support to the circuit board. The workability is improved, the lead wire is not necessary, the problem of short circuit between the lead wire and the circuit board is solved, and the reliability is improved.

Further, according to the present invention, since the piezoelectric transformer is supported in the width direction of the piezoelectric transformer, the total thickness including the support is minimized, and the height of the piezoelectric transformer can be reduced. In addition, the elastic support structure and the accurate support at the vibration node of the piezoelectric ceramic rectangular plate can prevent characteristic deterioration due to the support.

Further, the piezoelectric transformer supporting device of the present invention is
By bonding the insulating sheet to the bottom of the frame-shaped holder,
The insulation between the piezoelectric transformer and the circuit board becomes more reliable and reliability is improved, and if a material with a smooth surface and a low friction coefficient such as Teflon sheet is used, the piezoelectric transformer and the insulation sheet It is possible to prevent characteristic deterioration due to friction even when the two come into contact with each other.

Further, the piezoelectric transformer supporting device of the present invention is
The impact resistance can be improved by injecting flexible silicone into the gap between the piezoelectric transformer and the frame-shaped holder.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a piezoelectric transformer support device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a piezoelectric transformer supporting device according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a piezoelectric transformer support device according to a third embodiment of the present invention.

FIG. 4 shows an example of a piezoelectric transformer, (a) is a perspective view of a state before connecting the first counter electrode and the third counter electrode, and (b) is a first counter electrode and the third counter electrode. It is a perspective view of the state where the counter electrode was connected.

FIG. 5 is a diagram illustrating the operating principle of the piezoelectric transformer.

FIG. 6 shows a main part of a conventional piezoelectric transformer supporting device,
(A) is a perspective view of a support tool, (b) is a perspective view of a state where the support tool shown in (a) is mounted on a piezoelectric transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric transformer supporting device 2 Frame-shaped holder 3 Supporting tool 4 Insulating sheet 5 Flexible silicone 8 Circuit board 11 Piezoelectric transformer 12 Piezoelectric ceramic rectangular plate 15 Second counter electrode 16 Second counter electrode 20 Recess 21 Groove 30 Board mounting terminal 100 drive electrode 101 drive electrode

Claims (3)

[Claims] 1. A piezoelectric transformer supporting device for supporting a piezoelectric transformer in which electrodes are provided on side surfaces of a piezoelectric ceramic rectangular plate, and a frame-shaped holder which is slightly larger than the piezoelectric transformer, and arranged in the frame-shaped holder. A plurality of pairs of supporting members for supporting the piezoelectric transformer at the nodes of vibration thereof, the supporting members being made of a material having elasticity and conductivity, and forming a pair of the piezoelectric transformer. A piezoelectric transformer support characterized in that it has a board mounting terminal that is supported so as to be sandwiched in the width direction, is in contact with the electrode and is electrically connected, and further projects to the outside of the frame-shaped holder. apparatus. 2. The piezoelectric transformer supporting device according to claim 1, wherein an insulating sheet is bonded to the bottom surface of the frame-shaped holder. 3. The piezoelectric transformer support device according to claim 1, wherein flexible silicone is injected into a gap between the piezoelectric transformer and the frame-shaped holder.