JPH08139384A - Method of mounting cylindrical piezoelectric transformer - Google Patents

Abstract

PURPOSE: To connect electrodes on the inner surface of a cylindrical piezoelectric transformer to an external circuit easily by a method wherein the knots of vibration are held by support jigs which are fixed to a circuit board or to a board for supporting a piezoelectric transformer device and the outside surface input electrode of the piezoelectric transformer is connected to the external circuit with the metallic support jig. CONSTITUTION: A cylindrical piezoelectric transformer 1 whose input part is provided on one end of a cylindrical piezoelectric unit and whose output part is provided on the other end is fixed to a circuit board 5. At that time, the knots of its vibration are held and fixed by metallic or resin supporting jigs 6 and 7 which are fixed to a circuit board 5 or to a board exclusively for holding the piezoelectric transformer device 1. The metallic supporting jig 7 is also used for connecting an outside surface electrode 2 among input electrodes to an external circuit. Or, a protective case 9 which is made of insulating material and has a cavity in which the cylindrical piezoelectric transformer device 1 is housed is employed and protrusions 10 which is made of insulating material and which support and fix the knots of the vibration of the device are provided on the inner surface of the cavity of the protective case 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical piezoelectric transformer used for voltage conversion.

[0002]

2. Description of the Related Art Piezoelectric transformers that have been studied in the past have mainly been of a rectangular flat plate type as shown in FIG. The arrow inside the piezoelectric body in the figure indicates the direction of polarization. On the other hand, as shown in, for example, Japanese Patent Laid-Open No. 61-189678, a so-called cylindrical piezoelectric transformer in which an input electrode and an output electrode are provided on a cylindrical piezoelectric body and polarized to form an input portion and an output portion. Is proposed. FIG. 18 shows an example thereof. Figure 18a) is an external view,
b) is a sectional view. In this cylindrical piezoelectric transformer, an input outer surface electrode 61 and an input inner surface electrode 62 are formed on one side,
The output electrode 63 is formed on the other end surface. This cylindrical piezoelectric transformer has an advantage that the area occupied on the circuit board can be made smaller than that of a conventional flat plate piezoelectric transformer having the same output. To give an example, in the case of a piezoelectric transformer of 140 kHz drive and an output of 1.5 W in one wavelength mode, the size of the piezoelectric element is 24 × 5 × 0.8 in the conventional flat plate type.
Although it is about t (mm), in the case of a tubular shape, the size may be 24 × outer diameter 3.0φ × inner diameter 2.0φ (mm). The height of electronic parts such as transistors and capacitors is generally about 3 mm, and it is not necessary to make the piezoelectric transformer too thin. In comparison with the strength of the element, the cylindrical shape is much stronger than the flat plate and is less likely to be damaged by an external force. Furthermore, the cylindrical element can be easily and inexpensively manufactured by extrusion molding, which is a kind of ceramic molding method. As described above, adopting the cylindrical piezoelectric transformer to configure the voltage conversion circuit has many advantages in terms of cost and reliability.

[0003]

At present, there are almost no examples in which a cylindrical piezoelectric transformer is actually manufactured, and the mounting method thereof has not been clarified. The above-mentioned "JP-A-61"
In "-189678", the mounting method, that is, the method of fixing the element and the method of connecting to the external circuit are not specified. In the case of the Rosen type piezoelectric transformer, a mounting method is generally used in which lead wires are soldered to the input electrode and the output electrode with a soldering iron, and the node of the vibration is fixed by some means. Also in the case of the cylindrical piezoelectric transformer, it is possible to solder the lead wire to the input electrode on the outer surface of the cylinder and the output electrode on the end surface of the power generation unit with a soldering iron. However, the step of soldering the lead wire requires skill, and the silver electrode easily peels off from the surface of the piezoelectric element in the vicinity of the soldering portion of the electrode, and there is a problem in reliability. Furthermore, in the case of a cylindrical piezoelectric transformer, one of the pair of input electrodes of the input section is located on the inner surface of the cylinder, so soldering the lead wire, especially to the node section that does not hinder the vibration of the element. Soldering is difficult. The problem of how to easily connect the electrodes on the inner surface of the cylinder to the external circuit had to be solved.
An object of the present invention is to provide a mounting method for a cylindrical piezoelectric transformer that solves the above problems.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for fixing a cylindrical piezoelectric transformer having an input section at one end of a cylindrical piezoelectric body and an output section at the other end to a circuit board. The vibration node is fixed by a metal or resin supporting jig that is fixed to the circuit board or a dedicated substrate for holding the piezoelectric transformer element, and the metal supporting jig is fixed among the input electrodes. It also serves to connect the outer surface electrode to an external circuit. Further, the present invention uses a protective case made of an insulating material that houses a cylindrical piezoelectric transformer element in a cavity therein, and the protective case has a protrusion made of an insulating material for supporting and fixing a node of vibration of the element. It is provided on the inner surface of the cavity. Further, the present invention uses a protective case made of an insulating material for accommodating the cylindrical piezoelectric transformer element in a cavity inside thereof, and the protective case supports and fixes the vibration node of the element and, at the same time, protects the outside of the input side cylinder. It is provided with a metal support jig that also plays a role of connecting the surface electrode and an external circuit. Further, the present invention relates to a method of connecting an inner surface electrode of an input side cylinder of a cylindrical piezoelectric transformer and an external circuit, by bending a metallic wire or thin plate having elasticity and inserting it into the inside of the cylinder. To make contact with. The present invention also provides a method of connecting an inner surface electrode of a cylinder of an input portion of a cylindrical piezoelectric transformer to an external circuit, by forming a conductive film on an end surface of the cylinder on the input portion side, and further connecting the cylinder end surface with a conductive film. Connection that is drawn from the in-cylinder surface electrode to the outer surface of the cylinder by forming a conductive film also at the outer surface end and providing a gap without a conductive film between the outer surface of the cylinder and the input outer surface electrode It forms a circuit. Further, the present invention provides either or both of a connection circuit connected to an inner surface electrode of a cylinder input portion formed at an outer surface end portion of the cylinder by the mounting method, or an outer surface electrode of a cylinder input portion. After winding the lead wire, the lead wire and the electrode are soldered to fix the lead wire to the electrode. The present invention also relates to a method for connecting an output electrode on an end face of an output portion of a cylindrical piezoelectric transformer to an external circuit, in which a connection circuit is connected in advance to an end of an outer surface of the cylinder adjacent to the end face of the cylinder of the output electrode. Is formed, a lead wire is wound around the connection circuit, and then the lead wire and the electrode are soldered to fix the lead wire to the output electrode. Further, the present invention provides a method for connecting an output electrode on an end surface of an output portion of a cylindrical piezoelectric transformer to an external circuit, in which a conductor to be connected to the external circuit is preliminarily provided in the vicinity of the output electrode surface or at a position in contact with the electrode surface. Placed on a supporting jig for electrically connecting the conductor and the output electrode surface with a conductive adhesive or the like and for supporting the node of the element of the cylindrical piezoelectric transformer, or on a peripheral component for supporting. The protrusions contact only the surface of the element and are not fixed to the element surface. Further, according to the present invention, in a cylindrical piezoelectric transformer driven in a vibration mode other than the half-wave vibration mode, after the input / output electrodes are formed and the polarization process is completed, the output side end face electrode, which is the antinode of vibration, is transferred to this output electrode. A connection circuit is formed on the outer surface of the cylinder of the piezoelectric body that reaches the nearest vibration node by printing conductive paint or vapor deposition of a metal thin film. The other node of vibration is B, and the cylindrical piezoelectric transformer is supported at two points A and B by using conductive members, and the input / output electrodes are electrically connected to the external circuit through the support points. It is a thing.

[0005]

The present invention relates to a method for fixing a cylindrical piezoelectric transformer element,
With respect to the connection method between each electrode and the external circuit, various simple and highly reliable methods can be realized. This will be described below. First, claim 1 will be described. Also in the case of the cylindrical piezoelectric transformer, similarly to the case of the flat plate piezoelectric transformer, fixing the vibration node does not hinder the vibration of the entire element. FIG. 14 shows the displacement distribution of the standing wave of the vibration in the one-wavelength mode and the half-wavelength mode.
FIG. 14 shows a side view of the cylindrical piezoelectric transformer element on the upper side, and shows the displacements of the half-wavelength mode and the one-wavelength mode on the lower side. In case of one wavelength mode, 1/1 of the total element length
In the case where the position of 4, 3/4 is in the half-wavelength mode, the position of 1/2 of the total length of the element becomes a node of vibration. By using a conductive material for fixing the vibration node,
It becomes possible to fix the element and at the same time to connect the input electrode on the outer surface of the input section cylinder to an external circuit on the circuit board on which the piezoelectric transformer is mounted. The conductive member serving as the supporting jig can be produced, for example, by appropriately processing a thin metal plate or wire having elasticity. FIG. 4 shows an example in which a thin plate of phosphor bronze is processed and fixed to a circuit board to form supporting jigs A and B in the case of the one-wavelength mode. In FIG. 4, 1 is a cylindrical piezoelectric transformer element, 2 is an input outer surface electrode, 3 is an output electrode, 4 is a lead wire, 5 is a circuit board, 6 is a supporting jig A, and 7 is a supporting jig B. In this case, the metal support jig B comes into contact with the element surface of the output section where there is no electrode. If this support jig B is not connected to the circuit and its potential is not bound to a specific value,
Although the supporting jig itself is charged with a high voltage, it hardly affects the characteristics of the piezoelectric transformer. However, if you want to prevent the support jig from becoming a high voltage in terms of safety,
It is better to change the support jig B to a resin one which is an insulator.

Next, claim 2 will be described. As mentioned earlier, the cylindrical piezoelectric transformer is stronger and less prone to damage than conventional plate-shaped piezoelectric transformers, but it is housed in a protective case made of an insulating material such as resin in order to further improve reliability. It is desirable to protect from impacts from Further, by providing the protective case with an external terminal for connecting to the circuit board, there is an advantage that the work of mounting the piezoelectric transformer on the circuit board is simplified. When the protective case is adopted in the one-wavelength mode, the vibration node in the output section is supported by the protrusions provided on the inner surface of the cavity that houses the piezoelectric transformer inside the protective case, and thus the element support jig is formed. It can be omitted and the work of fixing the element can be simplified.
An example of this is shown in FIG. 5 as a sectional view. FIG. 5 is a cross-sectional view of the output portion of the cylindrical piezoelectric transformer, and a protrusion 10 is formed on the protective case 9 corresponding to a portion of the cylindrical piezoelectric transformer element 1 that serves as a vibration node. The piezoelectric transformer element 1 is fixed with an insulating adhesive 11 at a portion. In order to ensure this fixing, it is desirable to apply an insulating adhesive to the projections before assembling the device.

Next, claim 3 will be described. When the protective case is used, the vibration node in the input section is fixed by fixing the element and mounting the external electrode on the outer surface of the cylinder by attaching the metal support jig described in claim 1 to the protective case. The connections between the circuits can be made simultaneously. An example in the case of the single wavelength mode is shown in FIG. After fixing the U-shaped metal supporting jig C13 in the figure to the protective case 12, the whole is turned over and mounted on the circuit board. Therefore, FIG.
The upper surface of the supporting jig C shown in FIG. 2 is a portion fixed to the circuit board by means of reflow or the like, and also serves as an external terminal.

Next, claim 4 will be described. Claim 3
Up to this point, the external surface side of the input electrode has been described, but this section relates to the internal surface side of the input electrode.
As shown in FIG. 6 as an example, a thin metal plate having elasticity is bent to form a supporting jig D14, which is inserted into a cylinder and the metal fitting is fixed at a position where the metal fitting comes into contact with a vibration node of the inner surface electrode. To do. In FIG. 6, this support jig D14 is fixed to the protective case 12 and also serves as an external terminal, like the above-mentioned support jig C13. The supporting jig D may be made of a metal wire having elasticity other than the thin plate shape. FIG. 7 shows an example of the case where the supporting jig is formed by using the metal wire rod in the case of the half wavelength mode. This support jig 15 is referred to as a support jig E for the purpose of distinguishing it from the others.

Next, claim 5 will be described. This also relates to the method of connecting the inner surface electrodes, as in the previous section.
In order to take out the connection circuit from the inner surface electrode to the outside,
As shown in the sectional view, a conductive film is formed on the surface of the piezoelectric body from the inner surface electrode 18 through the end face on the input portion side to the end of the outer surface of the cylinder by plating, applying a conductive paint or the like. To do. A gap having no conductive film is provided between the connection circuit 19 and the input outer surface electrode 17. The connection circuit 19 may be formed over the entire circumference of the cylinder, or, as shown in FIG. 9, the connection circuit 20 may be formed only on a part of the circumference of the cylinder. When a conductive paint is used, the paint may be a different type from the paint forming the electrode (usually a silver paste and baked at 400 to 900 ° C. after application), but the same kind should be used. The use of the element simplifies the manufacturing process of the element.

Next, claim 6 will be described. When connecting a portion of the connecting circuit at the end portion of the outer surface of the cylinder, which is formed by being connected to the inner surface electrode described in the preceding paragraph, to the external circuit, this portion is sandwiched and fixed by the support metal fittings as described in claim 1. Is not desirable. This is because the end portion of the input portion is an antinode of vibration, and fixing the vicinity of this portion impedes the vibration of the element and reduces the output and efficiency of the piezoelectric transformer. Therefore, a method that does not interfere with element vibration such as a lead wire should be used to connect this portion to an external circuit. Conventionally, the fixing of the lead wire to the electrode has been performed by soldering the lead wire using a soldering iron. The content of this claim is, for example,
The connection of the lead wire to the connection electrode where the input inner surface electrode described in claim 5 of the present invention is drawn out to the end portion of the outer surface of the cylinder is fixed by winding the lead wire around the cylindrical electrode portion. Then, the part where the lead wire of the element is wound is attached to the solder bath and pulled up to complete the soldering. FIG. 10 shows an example thereof. This Figure 1
In 0, a lead wire is wound around the connection circuit 19 and the input outer surface electrode 17. As also shown in FIG. 10, the lead wire can be fixed to the input outer surface electrode by a similar method. However, in this case, since it is impossible to immerse the portion around which the lead wire is wound in the solder bath, after winding the lead wire, a solder paste is applied onto the lead wire and heated to complete the soldering. These methods are easier to automate than the conventional soldering method using a soldering iron, and the connection of the lead wire to the electrode is firm, so that the reliability after fixing the lead wire is also improved.

Further, claim 7 will be described. The method of fixing the lead wire to the electrode described in claim 6 can be applied to the output electrode. As shown in FIG. 11, a connection circuit 22 that communicates with the output electrode 21 is provided in advance at the outermost end of the cylinder adjacent to the output electrode 21 on the end surface, and the lead wire 23 is provided in this connection circuit 22 portion. After winding, dip it in a solder bath and solder it. Since the output electrode is located on the end face of the cylinder, it was difficult to fix the lead wire, but this method allows the lead wire to be easily connected to the output electrode, and the reliability is also improved.

Further, claim 8 will be described. The content of this claim describes a method of connecting the output electrode and an external circuit without using a lead wire.
Fixing the output electrode, which is the antinode of vibration, to the conductor provided on the circuit board with a conductive adhesive, etc., and realizing electrical connection at the same time as fixing the element, as a result, it hinders the vibration of the element. It reduces power and efficiency and is not desirable.
This is because the distance between the node and the antinode of vibration expands and contracts as the element vibrates, so fixing the node and antinode at the same time hinders the vibration of the element. However, even if the output end is fixed,
While touching the element in the node of vibration of the element,
If the supporting jig that supports the element and plays the role of electrical connection to the electrode, or the protrusion for supporting the element is not fixed to the element surface, vibration of the element may be hindered. Absent. When such a mounting method is adopted, the output and efficiency of the piezoelectric transformer are slightly reduced as compared with the conventional mounting method in which the node of the element is fixed and the lead wire is connected to the output end electrode. According to the mounting method of the present invention, since it is not necessary to connect the lead wire to the element electrode, there is an advantage that the manufacturing process of the piezoelectric transformer is simplified. FIG. 12 shows a configuration diagram of an example of a half-wavelength mode in which the element output end is fixed using a conductive adhesive. In FIG. 12, 24 is a conductor, 25 is a conductive adhesive, 26 is a supporting jig, and 27 is a circuit board.

Further, claim 9 will be described. The contents of this section are also related to the omission of the lead wire of the output electrode as in the previous section. There is always at least one vibration node at the output of a cylindrical piezoelectric transformer that vibrates in modes other than half-wavelength mode. After the polarization is completed, the contents of this section are, on the outer surface of the cylindrical piezoelectric transformer element, from the output end electrode, which is the antinode of vibration, to the nearest vibration node (hereinafter referred to as node A). A connection circuit is formed by printing a conductive paint or vapor deposition of a metal thin film, and by supporting this vibration node A with a conductive member, the connection between the output electrode and the external circuit is realized. FIG. 13 shows an example of this mounting method. This figure relates to an element driven in the one-wavelength vibration mode, and the node of vibration inside the input electrode is designated as B, and the element is supported at two points A and B. The connection circuit 29 from the output electrode 28 to the node A is formed by applying a conductive paste on the surface of the piezoelectric body. Further, 30 and 31 are support jigs, and 32 is a circuit board. Here, in order to prevent an adverse effect on the element characteristics due to an increase in the output side parasitic capacitance caused by forming the connection circuit, it is preferable to make the area of the connection circuit as small as possible. Further, when the specific resistance of the element material is not so high, a thin film of an insulator may be formed on the element and a connection circuit may be formed on the thin film.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 shows Embodiment 1 of the present invention. This is an embodiment of claim 1, claim 5, claim 6, and claim 7 of the present invention. 1a) is a front view, and FIG. 1b) is AA in FIG. 1a).
It is a horizontal sectional view of a surface. In this embodiment, the cylindrical piezoelectric transformer 1 has an external terminal 33 for connecting to a circuit board,
It is mounted on a resin-made base component 35 having a barbed terminal 34 for connecting a lead wire 37 from a piezoelectric element. A silver paste as a conductive paint is applied to the cylindrical piezoelectric transformer element 1 at a predetermined position, heated to 520 ° C. to bake the silver paste to form each electrode, and the lead wire 37 is wound around each electrode and immersed in a solder bath. Then, the lead wire is fixed to the electrode. Then, a predetermined high voltage is applied between the electrodes to perform polarization. The support jig 36 is made by bending a thin plate of phosphor bronze, and is fixed on the base component 35 by a method such as fitting or adhesion. After the other end of the lead wire 37 is twisted to the twisted terminal 34, the terminal portion is dipped in a solder bath for soldering. The support jig 36 connected to the input outer surface electrode is electrically connected to one of the external terminals 33.

Embodiment 2 FIG. 2 shows Embodiment 2 of the present invention. This is an embodiment of claim 2, claim 3, claim 4, and claim 8 of the present invention. 2a) is a front view, FIG. 2b) is a bottom view, and FIG. 2c) is a side view from the left. The resinous protective case 38 has a protrusion 41 for holding the cylindrical piezoelectric transformer element 1 on its inner surface, and the element 1 is in contact with this protrusion 41 at its node. The end surface electrode 3 on the output side has a conductive adhesive 4 between the output terminal 39, which is a metal member fixed to the protective case 38, where the surface is exposed on the inner surface of the protective case 38.
It is glued by 0. The conductive adhesive 40 is as hard and strong as possible. The reason for this will be described later. In Example 2, silver filler particles are kneaded with an epoxy base adhesive. An input-side outer surface electrode 2 of the cylindrical piezoelectric transformer element 1,
External terminal 4 provided in advance in the protective case 38
The connection between the three is made by fitting a supporting jig F42, which is formed by bending an elastic metal wire, into the protective case 38. After being fitted, the metal wire is always in contact with the input side outer surface electrode 2 due to its elasticity. The space between the supporting jig F42 and the surface of the electrode is defined by claim 8.
As described in, the relative position is not fixed but the relative position is not fixed. A similar state exists between the protrusion on the inner surface of the protective case 38 and the element surface described above. The connection between the input-side inner surface electrode of the tubular piezoelectric transformer element 1 and the external terminal 45 of the protective case is performed by connecting the supporting jig G44, which is a similarly elastic metal wire, from the outside of the protective case to the tube of the piezoelectric transformer element. It is done by inserting inside. The ends of the supporting jig F42 and the supporting jig G44 are external terminals 43, 45.
By soaking it in a solder bath with the solder,
It is electrically connected to the external terminal. Here, the influence of the power conversion characteristics of the piezoelectric transformer by adopting this embodiment will be described. Table 1 shows the difference in output power and efficiency due to the difference in the mounting method of the piezoelectric transformer. Table 1
In the conventional example, when only the output electrode connection method of the mounting method of the second embodiment is changed and a lead wire is soldered to the output electrode, the example A is the second example, the comparative example A is the second example. When the support jig F42 of Example 2 and the input outer surface electrode 2 are bonded with an epoxy-based conductive adhesive, Example B is the same as the output-side fixing conductive adhesive of Example 2 from epoxy-based urethane. When the system is changed to Comparative Example B, Comparative Example B is a case where the support jig F42 and the input outer surface electrode 2 in Example B are bonded with an epoxy conductive adhesive. The measurement circuit is shown in Figure 15.
In the separately-excited oscillation circuit shown in (1), the frequency was changed in the vicinity of 140 kHz, and the output and power efficiency at the time when the output became maximum were obtained. The input voltage was 30 Vrms. Here, the conductive adhesive described as urethane-based is a urethane-based adhesive in which silver particles are kneaded and is flexible and rubber-like, and its pencil hardness is 5B. On the other hand, the conductive adhesive designated as epoxy is a mixture of silver particles in an epoxy adhesive, which is relatively hard and strong, and has a pencil hardness of 4H. The element size of the cylindrical piezoelectric transformer is 2 in total length.
4, the outer diameter is 2.8φ, and the inner diameter is 2.0φ (mm), and the conductive adhesive is applied to the entire surface of the output end face electrode.

[0017]

[Table 1]

As shown in Table 1, in Example 2, Comparative Example A in which the support jig 42 and the element surface were bonded together,
Both output power and power conversion efficiency are superior to B.
In the case of Example A using a hard epoxy-based conductive adhesive, a value comparable to that of the conventional example in which a lead wire was soldered to the output electrode was obtained, and the lead wire was omitted and the cylindrical piezoelectric material was omitted. It is possible to greatly simplify the mounting of the transformer element.

Third Embodiment FIG. 3 shows a third embodiment of the present invention. This is an embodiment of claim 2, claim 3, claim 4, and claim 9 of the present invention. FIG. 3 is a perspective view of each component of this embodiment. After the cylindrical piezoelectric transformer element 1 is polarized, a conductive paste having a length of 6.5 mm and a width of 0.5 mm is applied on the surface of the piezoelectric element from the output end to the vibration node of the output portion, and the output electrode connection circuit is formed. 29 is formed. By the way, the overall length of this cylindrical piezoelectric transformer element 1 is 24 mm, the outer diameter is 3.0 φ, and the inner diameter is 2.0 φ (m
m). The element is incorporated in a resin-made protective case 12 having a protrusion 46 on the inner surface of the inner cavity, and the protrusion 46 of the protective case 12 and the vibration node position of the cylindrical piezoelectric transformer element 1 are bonded with an insulating adhesive material. After fixing, the two U-shaped support jigs C13 are fitted into the protective case 12 to hold down the element. Support jig 13 and input outer surface electrode 2
In order to ensure an electrical connection between the output electrode connection circuit 29 and the output electrode connection circuit 29, a conductive adhesive may be used to bond the both. Next, the support jig D14 is inserted through the hole 47 provided in the protective case to complete the connection of the input inner surface electrode. The influence on the power conversion characteristics of the piezoelectric transformer when the lead wire is not used for the output electrode and the connection circuit on the outer surface of the piezoelectric element according to the present embodiment is used instead of the lead wire will be described below. The size of the element and the shape of the short circuit of the example are as described above. The size and material of the element of the comparative example are the same as those of the example, and only the point that the lead wire is soldered to the output electrode is different from the example. A circuit for measuring the output power and power conversion efficiency of the piezoelectric transformer is shown in FIG. The input power and the output power are measured by inputting the waveforms of the voltage and the current of the input and the output, respectively, while changing the oscillation frequency of the oscillator. The input voltage was 45 Vrms. The measurement results of output power and efficiency are shown in FIG. Although the efficiency of the example is slightly inferior to that of the comparative example, the output power is rather higher than that of the comparative example. It is considered that this is because, in the example, the parasitic capacitance on the output side of the piezoelectric element increased due to the formation of the connection circuit. In the case of the present embodiment, the number of parts constituting the piezoelectric transformer is small and the assembly is simple, and the completed piezoelectric transformer can be easily mounted on the circuit board.

[0020]

INDUSTRIAL APPLICABILITY The present invention can realize various methods for mounting a cylindrical piezoelectric transformer on a circuit board and electrically connecting each electrode and an external circuit. As a result,
Mounting a cylindrical piezoelectric transformer has become extremely simple.

[Brief description of drawings]

FIG. 1 is a front view a) of Embodiment 1 according to the present invention and its A-.
It is A sectional drawing b).

FIG. 2 is a front view a), a bottom view b) and a side view c) of a second embodiment according to the present invention.

FIG. 3 is an exploded perspective view of a third embodiment according to the present invention.

FIG. 4 is an explanatory perspective view related to claim 1 of the present invention.

FIG. 5 is an explanatory partial cross-sectional view relating to claim 2 of the present invention.

FIG. 6 is an explanatory partial perspective view relating to claims 3 and 4 of the present invention.

FIG. 7 is an explanatory partial cross-sectional view relating to claim 4 of the present invention.

FIG. 8 is an explanatory partial cross-sectional view related to claim 5 of the present invention.

FIG. 9 is an explanatory partial perspective view related to claim 5 of the present invention.

FIG. 10 is an explanatory partial perspective view relating to claim 6 of the present invention.

FIG. 11 is an explanatory partial perspective view relating to claim 7 of the present invention.

FIG. 12 is an explanatory front view of claim 8 of the present invention.

FIG. 13 is an explanatory front view related to claim 9 of the present invention.

FIG. 14 is a diagram showing a displacement amount of a cylindrical piezoelectric transformer element.

FIG. 15 is an evaluation circuit diagram of an example of the present invention.

FIG. 16 is a characteristic diagram of an example of the present invention and a conventional example.

FIG. 17 is a perspective view of a conventional Rosen type piezoelectric transformer element.

FIG. 18 is a perspective view a) and a sectional view b) of a conventional cylindrical piezoelectric transformer element.

[Explanation of symbols]

1,16 Cylindrical piezoelectric transformer element 2,17 Input outer surface electrode 3,21,28 Output electrode 4 Lead wire 5,27,32 Circuit board 6,7,13,14,15,26,30,31,36,
42,44 Support jig 8,18 Input inner surface electrode 9,12,38 Protective case 10,41,46 Protrusion 11 Insulating adhesive 19 Inner surface electrode connection circuit 20,23,37 Lead wire 22,29 Output electrode Connection circuit 24 Conductor 25,40 Conductive adhesive 33,43,45 External terminal 34 Bark terminal 35 Resin base part 39 Output terminal 47 hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeru Sadamura Inventor Shigeru Tottori, 33-12 Minamieicho, Tottori-shi, Hitachi Ferrite Co., Ltd. (72) Inventor Yasushi Shimoda 33-12 Minamiei-cho, Tottori, Tottori Ito Corporation

Claims (9)

[Claims] 1. A method for fixing a cylindrical piezoelectric transformer, wherein an input portion is provided at one end of a cylindrical piezoelectric body and an output portion is provided at the other end thereof to a circuit board, and the vibration node is used as a circuit board or Fix it with a metal or resin supporting jig that is fixed to the dedicated substrate for holding the piezoelectric transformer element,
A method for mounting a cylindrical piezoelectric transformer, wherein the metal supporting jig also serves to connect an outer surface electrode of the input electrodes to an external circuit. 2. A protective case made of an insulating material for accommodating a cylindrical piezoelectric transformer element in a cavity therein is used, and the protective case has a protrusion made of an insulating material for supporting and fixing a node of vibration of the element. A method for mounting a cylindrical piezoelectric transformer, which is provided on the inner surface of the cavity. 3. A protective case made of an insulating material for accommodating a cylindrical piezoelectric transformer element in a cavity inside thereof is used. The protective case supports and fixes a vibration node of the element, and at the same time, the outside of the cylinder on the input side. A method of mounting a cylindrical piezoelectric transformer, comprising a metal supporting jig that also plays a role of connecting a surface electrode and an external circuit. 4. A method for connecting an inner surface electrode of an input side cylinder of a cylindrical piezoelectric transformer and an external circuit, wherein a metallic wire or thin plate having elasticity is bent and inserted into the inside of the cylinder, and this inner surface electrode A method for mounting a cylindrical piezoelectric transformer, which is characterized in that it is brought into contact with. 5. A method for connecting an inner surface electrode of an input side cylinder of a cylindrical piezoelectric transformer and an external circuit, wherein a conductive film is formed on an end surface of the cylinder on the input side, and the cylinder is connected to the end surface of the cylinder. Connection that is drawn from the in-cylinder surface electrode to the outer surface of the cylinder by forming a conductive film also at the outer surface end and providing a gap without a conductive film between the outer surface of the cylinder and the input outer surface electrode A method for mounting a cylindrical piezoelectric transformer, which comprises forming a circuit. 6. A connecting circuit connected to an inner surface electrode of an input portion of a cylinder formed at an outer surface end portion of the cylinder by the mounting method according to claim 5 of the invention, or an input portion of the cylinder. A method for mounting a cylindrical piezoelectric transformer, comprising: winding a lead wire around one or both of the outer surface electrodes, and then fixing the lead wire to the electrode by soldering between the lead wire and the electrode. 7. A method of connecting an output electrode on an end surface of an output portion of a cylindrical piezoelectric transformer to an external circuit, wherein a connection circuit is connected to an end portion of an outer surface of the cylinder adjacent to the end surface of the output electrode on the cylinder in advance. Is formed in advance, the lead wire is wound around the connection circuit, and then the lead wire is fixed to the output electrode by soldering between the lead wire and the electrode. 8. A method for connecting an output electrode on an end face of an output portion of a cylindrical piezoelectric transformer to an external circuit, in which a conductor to be connected to the external circuit is preliminarily provided in the vicinity of the output electrode surface or at a position in contact with the electrode surface. Placed on a supporting jig for electrically connecting the conductor and the output electrode surface with a conductive adhesive or the like and for supporting the node of the element of the cylindrical piezoelectric transformer, or on a peripheral component for supporting. A method for mounting a cylindrical piezoelectric transformer, wherein the protrusion is in contact with the surface of the element but is not fixed to the surface of the element. 9. A tubular piezoelectric transformer driven in a vibration mode other than a half-wave vibration mode, after an input / output electrode is formed and a polarization process is completed, an output side end face electrode, which is an antinode of vibration, is connected to this output electrode. A connection circuit is formed on the outer surface of the cylinder of the piezoelectric body that reaches the nearest vibration node by printing conductive paint or vapor deposition of a metal thin film. The other vibration nodes in B
A cylindrical piezoelectric transformer is supported at two points A and B by using a conductive member, and the input / output electrodes are electrically connected to an external circuit through the supporting points. How to implement.