JP3663524B2 - Piezoelectric transformer - Google Patents

Description

【００２８】
【発明の効果】
本発明による圧電トランスは、矩形板の共振振動の節上にて、矩形板の幅方向に延び、かつ矩形板の厚さ方向に積層する節上積層電極層を有し、節上積層電極層が、その一端部が矩形板の一方の長側面にまで達している一方、他端部が矩形板の他方の長側面よりも所定距離をおいて矩形板内にとどまっており、さらに、矩形板の一方の長側面上にて、節上積層電極層の一端部に接続する節上側面電極層を有しているため、矩形板の共振振動に十分耐え得る外部接続構造と、電位差の大きい端子間の絶縁の確保との両方を実現し得る。
【００２９】
また、電位差の大きい端子間の絶縁を確保するために配線の引き回し方が規制されることがなく、配線の引き回しの自由度が高いので、製品設計上の自由度が高い。
【図面の簡単な説明】
【図１】本発明の実施の一形態による圧電トランスを示す概略的な斜視図である。
【図２】（ａ）〜（ｄ）はそれぞれ、図１における圧電トランスの切断面Ａ−Ａ、Ｂ−Ｂ、Ｃ−Ｃ、Ｄ−Ｄによる縦断面図である。
【図３】従来例による圧電トランスを示す概略的な斜視図である。
【図４】（ａ）〜（ｄ）はそれぞれ、図３における圧電トランスの切断面Ａ′−Ａ′、Ｂ′−Ｂ′、Ｃ′−Ｃ′、Ｄ′−Ｄ′による縦断面図である。
【図５】（ａ）ならびに（ｂ）はそれぞれ、図３に示す圧電トランスの切断面Ｅ′−Ｅ′による縦断面図ならびにこの縦断面図に対応する圧電トランスの矩形板の長さ方向における変位分布および応力分布を示す図である。
【符号の説明】
１０ 圧電トランス
１１ 矩形板
１２、１３ 積層電極層
１４、１５、１９ 節上側面電極層
１６、２０ 節外積層電極層
１７ａ、１７ｂ、２１ａ、２１ｂ、２１ｃ 節外側面電極層
１８ 節上積層電極層
３０ ＦＰＣ
３１ ポリイミド膜
３２ｃ 節上端子パターン
３２ａ、３２ｂ 節外端子パターン
３３ 配線パターン
４０ リード線[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric transformer using a resonance mode in a longitudinal direction of a rectangular plate (piezoelectric vibrator) made of piezoelectric ceramics, and more particularly to improvement of the structure of the rectangular plate.
[0002]
[Prior art]
Although a large current value is not required for the backlight of the static electricity generator or the liquid crystal display, a high voltage power supply device of about 1 kV and several watts is used. For such devices, piezoelectric transformers are being put into practical use due to demands for reducing generated electromagnetic noise, lowering power consumption, and reducing the size and height of equipment.
[0003]
FIG. 3 is a schematic perspective view showing a conventional piezoelectric transformer. 4 (a), (b), (c), and (d) are sectional views A'-A ', B'-B', C'-C ', and D' of the piezoelectric transformer in FIG. 3, respectively. It is a longitudinal cross-sectional view by -D '. 5 (a) and 5 (b) are longitudinal sectional views of the piezoelectric transformer taken along line E'-E 'in FIG. 3, and the displacement in the longitudinal direction of the rectangular plate of the piezoelectric transformer corresponding to the longitudinal sectional view. It is a figure which shows distribution (solid line) and stress distribution (broken line).
[0004]
Referring to FIG. 3 and FIGS. 4A to 4D, a conventional piezoelectric transformer 60 has a rectangular plate 61 (total length L = L ′ × 4) made of piezoelectric ceramics. In FIG. 3 and FIG. 4A, the arrow indicates the polarization direction.
[0005]
The rectangular plate 61 is virtually divided into one and the other in the length direction (left-right direction in FIG. 3).
[0006]
In one section of the rectangular plate 61 (on the left side in FIG. 3), the laminated electrode layers 62 and 63 which have an area covering almost the whole area and alternately oppose each other at a predetermined interval in the thickness direction of the rectangular plate 61, Nodal side electrode layers 64 and 65 connected to the laminated electrode layers 62 and 63, respectively, at a position L / 4 from the left end in the figure on the long side of the rectangular plate 61 (on the resonance vibration node of the rectangular plate 61); have.
[0007]
In the other section (right side in FIG. 3) of the rectangular plate 61, the rectangular plate 61 is rectangular at a position L / 2 from the left end in FIG. 3 (on the maximum displacement point (antinode) of the resonance vibration of the rectangular plate 61). The outer electrode layered electrode layer 66 that extends in the width direction of the plate 61 so as to reach the long side surface of the rectangular plate 61 and is opposed to the rectangular plate 61 at a predetermined interval in the thickness direction of the rectangular plate 61, On both long sides, the outer-node-side electrode layers 67a and 67b connected to both ends of the outer-node laminated electrode layer 66 and the position of the rectangular plate 61 at L × (3/4) from the left end in FIG. 61), both ends of the rectangular plate 61 extend in the width direction so as to reach the long side surface of the rectangular plate 61, and face each other at a predetermined interval in the thickness direction of the rectangular plate 61. On the nodal laminated electrode layer 68 and on the long side surfaces of the rectangular plate 61, the nodal joint connected to both ends of the nodal laminated electrode layer 68 The surface electrode layers 69a and 69b and the rectangular plate 61 are both rectangular in the width direction of the rectangular plate 61 at a position L from the left end of the rectangular plate 61 in FIG. An extranodal laminated electrode layer 70 extending to reach the long side surface of the plate 61 and facing the rectangular plate 61 at a predetermined interval in the thickness direction, and extranodal lamination on both long side surfaces of the rectangular plate 61 The outer side electrode layers 71a and 71b connected to both ends of the electrode layer 70, and the side end of the outer electrode layer electrode layer 70 and the outer node electrode layer on the short side surface of the rectangular plate 61 on the right side in FIG. And a node outer surface electrode layer 71c connected to 71a and 71b.
[0008]
In the piezoelectric transformer 60, for example, the nodal upper side electrode layers 64 and 65 are used as input terminals, the nodal outer side electrode layer 67a and the nodal outer side electrode layer 71a are used as ground terminals, and the nodal upper side electrode layers are used. 69a may be used as an output terminal.
[0009]
That is, an input signal having a frequency equal to one wavelength at the time of resonance with respect to the lengthwise dimension of the rectangular plate 61 is provided between the nodal side electrode layer 64 and the nodal side electrode layer 65 as input terminals. When an input is made and the nodal outer side electrode layer 67a and the nodal outer side electrode layer 71a as ground terminals are grounded, a high voltage is output from the nodal upper side electrode layer 69a as an output terminal. More specifically, when the step-up ratio of the piezoelectric transformer 60 is preferably 100 or more for the above-described application, the output from the nodal upper side electrode layer 69a when the input voltage is 10 V is 1 kV or more. FIG. 5B shows a vibration mode of the piezoelectric transformer 60 (rectangular plate 61) when each electrode layer is assigned as each terminal as described above.
[0010]
[Problems to be solved by the invention]
By the way, when the piezoelectric transformer is used, as described above, the nodal upper side electrode layer and the nodal outer side electrode layer are used as various terminals, and external connection means such as contacts and lead wires are attached to these terminals.
[0011]
Here, when the piezoelectric transformer is used, there is a possibility that the connection relationship of the connection portion of the external connection means is cut or a contact failure occurs due to the resonance vibration of the rectangular plate. For this reason, it is preferable that the connection portion is positioned on the node of the resonance vibration of the rectangular plate so that the resonance vibration of the rectangular plate is not applied to the connection portion as much as possible.
[0012]
If this is applied to the examples shown in FIGS. 3 to 5, external connection means such as lead wires are not directly connected to the nodal outer surface electrode layer 67a and the nodal outer surface electrode layer 71a located at the antinodes of vibration. Without connection, first, a flexible wiring pattern is routed from the nodal outer surface electrode layer 67a and the nodal outer surface electrode layer 71a to the vibration node, and external connection means is attached on the vibration node. Note that the wiring pattern in this case does not pass through the antinodes of other resonance vibrations from the resonance vibration nodes where the node outer surface electrode layer 67a and the node outer surface electrode layer 71a exist to the nodes of the resonance vibrations. Needless to say, it is preferable. That is, the node of the resonance vibration in this example is preferably a node at a position of ((3/4) × L) in FIG.
[0013]
Therefore, a flexible wiring pattern is routed from the node outer surface electrode layer 67a and the node outer surface electrode layer 71a to the node at the position ((3/4) × L) in FIG. External connection means will be attached on top. On this node, however, there are upper node side electrode layers 69a and 69b which are used as output terminals and output a high voltage. On the other hand, the wiring pattern from the outer node surface electrode layer 67a and the outer node surface electrode layer 71a relates to the ground terminal. The wiring pattern is usually insulated because it uses an FPC formed by forming a conductor pattern on an insulating flexible film. However, it is not sufficient and reliable to ensure insulation only by passing a single flexible film between the terminals having a large potential difference between the output terminal and the ground terminal.
[0014]
The subject of this invention is providing the piezoelectric transformer which can implement | achieve both the external connection structure which can fully endure the resonant vibration of a rectangular plate, and ensuring of insulation between terminals with a large potential difference.
[0015]
[Means for Solving the Problems]
According to the present invention, in the step-up piezoelectric transformer (10) using the resonance mode in the longitudinal direction of the rectangular plate (11) made of piezoelectric ceramics, on the node of the resonance vibration of the rectangular plate (11). And an output nodal laminated electrode layer (18) extending in the width direction of the rectangular plate (11) and laminated in the thickness direction of the rectangular plate (11). 18), one end of which reaches one long side of the rectangular plate (11), and the other end of the rectangular plate (11) is spaced a predetermined distance from the other long side. An output upper side electrode connected to one end of the output upper laminated electrode layer (18) on one long side of the rectangular plate (11). a layer (19), furthermore, at the upper than node of the resonant vibration of the rectangular plate (11), wherein An output extra-node layered electrode layer extending in the width direction of the shape plate (11) so that at least the other end reaches the other long side surface of the rectangular plate and is laminated in the thickness direction of the rectangular plate (11) (16, 20) and on the other long side surface of the rectangular plate (11), an output outer surface electrode layer for output connected to the other end of the output extra-node laminated electrode layer (16, 20) ( 17a, 21a), an output nodal terminal pattern (32c) provided on a node of resonance vibration of the rectangular plate (11) on the other long side surface of the rectangular plate (11), and flexibility And a wiring pattern extending between the output nodal outer surface electrode layer (17a, 21a) and the output nodal terminal pattern (32c) on the other long side surface of the rectangular plate (11). 33) and has a said rectangular plate (11) includes an input section and arranged along its length Is divided into a force indicator, said output node on laminated electrode layer (18), the output node on the side electrode layer (19), the output extranodal laminated electrode layer (16, 20), the output node outer surface The electrode layers (17a, 21a) and the output nodal upper terminal pattern (32c) are formed in the output section, and the input section is polarized in the thickness direction of the rectangular plate (11). the output segment, the length of the rectangular plate (11), and said output node on the laminated electrode layers sandwiching the (18) is polarized into two directions opposed, the upper output node Each of the side electrode layer (19) and the output nodal upper terminal pattern (32c) is used as a terminal for connecting an external connection means, thereby obtaining a piezoelectric transformer.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a piezoelectric transformer according to an embodiment of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a schematic perspective view showing a piezoelectric transformer according to an embodiment of the present invention. 2 (a), (b), (c), and (d) are longitudinal sectional views taken along section planes AA, BB, CC, and DD, respectively, of the piezoelectric transformer in FIG. is there.
[0019]
Referring to FIG. 1 and FIGS. 2A to 2D, a piezoelectric transformer 10 according to the present embodiment has a rectangular plate 11 (total length L = L ′ × 4) made of piezoelectric ceramics as in the conventional example. Have. In FIG. 1 and FIG. 2A, the arrow indicates the polarization direction. The rectangular plate 11 is virtually divided into one and the other in the length direction (left-right direction in FIG. 1). In one section of the rectangular plate 11 (on the left side in FIG. 1), the laminated electrode layers 12 and 13 which have an area covering almost the whole area and alternately oppose each other at a predetermined interval in the thickness direction of the rectangular plate 11, Nodal side electrode layers 14 and 15 connected to the laminated electrode layers 12 and 13, respectively, at a position L / 4 from the left end in the figure on the long side of the rectangular plate 11 (on the node of resonance vibration of the rectangular plate 11); have.
[0020]
In the other section of the rectangular plate 11 (right side in FIG. 1), the width direction of the rectangular plate 11 is at a position L / 2 from the left end of the rectangular plate 11 in FIG. 1 (on the antinode of resonance vibration of the rectangular plate 11). And the both ends of the rectangular plate 11 extending to reach the long side surface of the rectangular plate 11 and facing each other at a predetermined interval in the thickness direction of the rectangular plate 11. The outer-node-side electrode layers 17a and 17b connected to both ends of the outer-node laminated electrode layer 16 and the position L × (3/4) from the left end of the rectangular plate 11 in FIG. In the width direction of the rectangular plate 11, one end portion reaches one long side surface (the other side in FIG. 1) of the rectangular plate 11, while the other end portion is the other side of the rectangular plate 11. Extending to stay in the rectangular plate 11 at a predetermined distance from the long side surface (front side in FIG. 1), and the thickness of the rectangular plate 11 A nodal upper electrode layer 18 that is opposed to the nodal laminated plate layer 18 on one long side surface of the rectangular plate 11, and a rectangular plate 11. 11 extends from the left end of FIG. 1 to the position L (on the antinode of the resonance vibration of the rectangular plate 11) so that both end portions reach the long side surface of the rectangular plate 11 in the width direction of the rectangular plate 11, and 11 on the long side surface of the rectangular plate 11 and the nodal outer side electrode layer 21a connected to both ends of the extranodal laminated electrode layer 20 on both long sides of the rectangular plate 11. 1 and 21b, and on the short side surface of the rectangular plate 11 on the right side in FIG. 1, there are provided the outer end surface electrode layer 21c connected to the side end portion of the outer node stacked electrode layer 20 and the outer node surface electrode layers 21a and 21b. doing.
[0021]
Further, the piezoelectric transformer 10 has an FPC 30 as wiring means. The FPC 30 is located on the other long side surface of the rectangular plate 11 at a position of L × (3/4) from the left end of the rectangular plate 11 in FIG. 1 (on the resonance vibration node of the rectangular plate 11). On the other long side surface of the rectangular plate 11, the terminal pattern 32 c (thickness 0.3 mm) and the extra-node terminal patterns 32 a and 32 b (thickness 0.3 mm) connected to the outer node surface electrode layers 17 a and 21 a, respectively. ) And the other long side surface of the rectangular plate 11, flexible wiring extending between the outer node surface electrode layers 17 a and 21 a (outer node terminal patterns 32 a and 32 b) and the upper node pattern 32 c. A pattern 33 (thickness 0.3 mm) and a flexible insulating polyimide film 31 covering each terminal pattern and the wiring pattern 33 are provided. However, the outer surface of the nodal upper terminal pattern 32c is not covered with the polyimide film 31, and the inner surface of the outer nodal terminal patterns 32a and 32b is in contact with the nodal outer surface electrode layers 17a and 21a. 31 is not covered.
[0022]
The nodal upper side electrode layers 14 and 15 are connected to lead wires 40 for use as input terminals. Further, the nodal upper surface electrode layer 17a and the nodal upper surface electrode layer 32a connected to the nodal outer surface electrode layer 21a are connected to the lead wire 40 for use as a ground terminal. Further, the nodal upper side electrode layer 19 is connected to a lead wire 40 for use as an output terminal.
[0023]
Next, a method for manufacturing the piezoelectric transformer 10 will be described. The piezoelectric transformer 10 was manufactured as follows. First, a plurality of green sheets are formed using slips of high-Qm PZT piezoelectric ceramics. Each laminated electrode layer is printed on each green sheet with an electrode paste made of silver-palladium. After a plurality of green sheets are stacked and pressure-bonded, they are cut into a width of approximately 6 mm and a length of approximately 42 mm. Binder removal is performed, and sintering is performed at 110 ° C. for 2 hours in the air. Each side electrode layer is baked on the long side surface and one short side surface of the sintered body. After that, polarization treatment was performed in 150 ° C. silicon oil with an electric field strength of 1 kV / mm to obtain a rectangular plate 11 on which each electrode layer was formed. The external dimensions of the rectangular plate 11 are 6 mm wide × 42 mm long × 2 mm thick.
[0024]
An FPC 30 is formed on the other long side surface of the rectangular plate 11 on which each electrode layer is formed. The polyimide film 31 is adhered on the other long side surface of the rectangular plate 11, and the external node patterns 32a and 32b are bonded to the external surface electrode layers 17a and 21a, respectively. Furthermore, the lead wire 40 is joined to the node upper side electrode layers 14 and 15, the node upper terminal pattern 32 c, and the node upper side electrode layer 19. That is, any of the lead wires 40 is taken out from the vibration node.
[0025]
The insulation characteristics between the output terminal and the ground terminal of the piezoelectric transformer 10 manufactured as described above were tested. As a comparative example of the piezoelectric transformer 10, the conventional piezoelectric transformer 60 shown in FIGS. 3 to 5 is manufactured to the same material, shape and size as the piezoelectric transformer 10, and further, the same wiring means as the FPC 30 is formed. The same test was conducted for this comparative example.
[0026]
This test evaluates the dielectric strength between the output terminal and the ground terminal when a load (cold cathode tube) is actually connected to the piezoelectric transformer. A cold cathode tube having a diameter of 2.6 mm and a length of 220 mm was used. In the test method, a separately-excited sine wave is input to the piezoelectric transformer and the input voltage is gradually increased. The test results are shown in Table 1 below.
[0027]
[Table 1]

[0028]
【The invention's effect】
The piezoelectric transformer according to the present invention has a nodal laminated electrode layer that extends in the width direction of the rectangular plate and is laminated in the thickness direction of the rectangular plate on the resonance vibration node of the rectangular plate. However, one end of the rectangular plate reaches one long side of the rectangular plate, while the other end remains in the rectangular plate at a predetermined distance from the other long side of the rectangular plate. On one of the long sides, the external connection structure that can sufficiently withstand the resonance vibration of the rectangular plate and the terminal having a large potential difference are provided. It is possible to achieve both insulation between the two.
[0029]
In addition, the wiring routing method is not restricted in order to ensure insulation between terminals having a large potential difference, and the wiring routing flexibility is high, so that the freedom in product design is high.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a piezoelectric transformer according to an embodiment of the present invention.
2A to 2D are longitudinal sectional views taken along section planes AA, BB, CC, and DD of the piezoelectric transformer in FIG. 1, respectively.
FIG. 3 is a schematic perspective view showing a conventional piezoelectric transformer.
4A to 4D are longitudinal sectional views taken along section planes A′-A ′, B′-B ′, C′-C ′, and D′-D ′ of the piezoelectric transformer in FIG. 3, respectively. is there.
5 (a) and 5 (b) are respectively a longitudinal sectional view of the piezoelectric transformer shown in FIG. 3 taken along a cutting plane E′-E ′ and a longitudinal direction of a rectangular plate of the piezoelectric transformer corresponding to the longitudinal sectional view. It is a figure which shows displacement distribution and stress distribution.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Piezoelectric transformer 11 Rectangular plate 12, 13 Laminated electrode layers 14, 15, 19 Nodal upper side electrode layer 16, 20 Outer nodal laminated electrode layer 17a, 17b, 21a, 21b, 21c Nodal outer side electrode layer 18 Nodal laminated electrode layer 30 FPC
31 Polyimide film 32c Terminal pattern 32a, 32b Outside terminal pattern 33 Wiring pattern 40 Lead wire

Claims (1)

In a step-up type piezoelectric transformer using a resonance mode in the length direction of a rectangular plate made of piezoelectric ceramics,
On the node of the resonance vibration of the rectangular plate, it has an output nodal laminated electrode layer that extends in the width direction of the rectangular plate and is laminated in the thickness direction of the rectangular plate,
The output nodal multi-layer electrode layer has one end portion reaching one long side surface of the rectangular plate, and the other end portion having a predetermined distance from the other long side surface of the rectangular plate. Stays in the board,
Furthermore, on one long side of the rectangular plate, an output nodal side electrode layer connected to one end of the output nodal laminated electrode layer,
Furthermore, on a portion other than the resonance vibration node of the rectangular plate, at least the other end extends in the width direction of the rectangular plate so as to reach the other long side surface of the rectangular plate, and the thickness of the rectangular plate An extra-node laminated electrode layer for output laminated in a direction;
On the other long side surface of the rectangular plate, the output outer surface electrode layer connected to the other end of the output outer stacked electrode layer,
On the other long side of the rectangular plate, an output nodal terminal pattern provided on a node of resonance vibration of the rectangular plate;
A wiring pattern having flexibility and extending on the other long side surface of the rectangular plate between the output node outer surface electrode layer and the output node terminal pattern;
The rectangular plate is divided into an input section and an output section arranged along its length direction,
The output nodal multi-layer electrode layer , the output nodal side electrode layer , the output nodal multi-layer electrode layer, the output nodal outer side electrode layer, and the output nodal terminal pattern are in the output section. Formed,
The input section is polarized in the thickness direction of the rectangular plate,
The output section is polarized in two directions facing each other across the length of the rectangular plate and sandwiching the output nodal laminated electrode layer ,
The output transformer upper side electrode layer and the output joint terminal pattern are used as terminals for connecting external connection means, respectively .

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