WO1996031910A1 - Transformateur piezo-electrique - Google Patents

Transformateur piezo-electrique Download PDF

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Publication number
WO1996031910A1
WO1996031910A1 PCT/JP1996/000904 JP9600904W WO9631910A1 WO 1996031910 A1 WO1996031910 A1 WO 1996031910A1 JP 9600904 W JP9600904 W JP 9600904W WO 9631910 A1 WO9631910 A1 WO 9631910A1
Authority
WO
WIPO (PCT)
Prior art keywords
piezoelectric transformer
piezoelectric
polarization
thin plate
rectangular thin
Prior art date
Application number
PCT/JP1996/000904
Other languages
English (en)
Japanese (ja)
Inventor
Akira Tokushima
Original Assignee
Akira Tokushima
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP7116267A external-priority patent/JPH08279632A/ja
Priority claimed from JP7145113A external-priority patent/JPH08306983A/ja
Application filed by Akira Tokushima filed Critical Akira Tokushima
Publication of WO1996031910A1 publication Critical patent/WO1996031910A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/40—Piezoelectric or electrostrictive devices with electrical input and electrical output, e.g. functioning as transformers

Definitions

  • the present invention relates generally to a piezoelectric element or an electric-mechanical quantity conversion element composed of piezoelectric ceramics, and more particularly to a transistor used for a lighting device of a discharge lamp such as a cold cathode discharge lamp.
  • the present invention also relates to a piezoelectric transformer that can convert an electric signal acting as a transducer into a mechanical displacement, and convert a mechanical displacement into an electric signal.
  • a liquid crystal display device is used as a display unit, and a circuit including a piezoelectric transformer is used to drive a cold cathode discharge lamp, which is a light source for illumination.
  • the above-mentioned piezoelectric transformers that have been conventionally developed are long in the length direction and are mainly intended for voltage amplification to obtain a high voltage at the output side.
  • the length-to-width dimensional ratio is usually set to 0.2 or less.
  • the width W be less than about 30 of the length L in order to drive the length vibration stably.
  • the specific dimensions of the piezoelectric transformer are W 15 mm in width, L 85 mra in length, and T 2 mm in thickness. The ratio is 0.18.
  • Discharge tube post-robo light source etc.
  • both a high voltage and an output current of at least about 1 to 1 OmA are required at the same time.
  • a high input voltage of, for example, about 40 V to 70 V has been applied. Therefore, at a battery voltage of 6 V to 12 V, the discharge tube and the strobe light source emit light only at low luminance, making it impractical.
  • a boost-matching transformer was required, the drive and control circuits were complicated and expensive, and the range of use was narrow.
  • the input and output impedances are both defined as high impedance, so that the drive and control devices such as the preceding amplifier and the subsequent Matching with the actual load was not considered at all.
  • the present invention is different from the conventional voltage amplification type piezoelectric transformer using the vibration mode having a long length, and is capable of simultaneously performing current amplification.
  • the purpose of this method is to obtain a flow-width type piezoelectric transformer.By applying the vibration mode in the width direction of the contour vibration, which has strong vibration characteristics, it is possible to achieve both high pressure and large output current.
  • the task is to obtain a pressure transformer that can be obtained.
  • the drive side including the transmission unit, the drive unit, and the piezoelectric transformer, the discharge tube flash light source, and the like are used.
  • the drive side including the transmission unit, the drive unit, and the piezoelectric transformer, the discharge tube flash light source, and the like are used.
  • the task is to obtain a low-input, low-output chime-beading piezotransform as an input chime-beadin of less than 100 ohms and an output chiefly bead of less than 100 kiloohms.
  • the capacitance of the thickness direction polarization which is the input part of the voltage S trans, is in the range of 500 to 450 pF, and the output part is
  • the static capacitance of the longitudinal polarization section must be within the range of 10 to 4 OO pF. It is an object of the present invention to obtain a formed piezoelectric transformer and to suppress unnecessary vibration that occurs during driving when a relatively high voltage of the piezoelectric transformer is used. Disclosure of the invention
  • the piezoelectric transformer according to the present invention is constituted by a lengthwise polarization part and a thickness direction polarization part made of piezoelectric ceramics, and the resonance characteristics in the thickness direction and the resonance characteristics in the length direction are substantially matched.
  • the thickness direction polarization part is used as an input part
  • the length direction polarization part is used as an output part
  • the resonance characteristic of either the input part or the output part is adjusted.
  • FIG. 1 is a perspective view showing an embodiment of a piezoelectric transformer according to the present invention.
  • FIG. 2 is a perspective view showing another embodiment of the piezoelectric transformer according to the present invention.
  • FIG. 3 is a diagram showing the resonance characteristics of the polarization section of the piezoelectric trans- former in the thickness direction.
  • FIG. 4 is a diagram showing the resonance characteristics of the longitudinally polarized portion of the piezoelectric transformer.
  • FIG. 5 is a perspective view showing still another embodiment of the piezoelectric transformer according to the present invention.
  • FIG. 6 is a perspective view showing a method for fixing a piezoelectric transformer according to the present invention.
  • BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 shows an embodiment of the piezoelectric transformer of the present invention.
  • One side of the piezoelectric transformer made of the piezoelectric ceramic C is formed in a rectangular thin plate shape, and has one of the lengths and widths of the length and width of the rectangular thin plate-shaped piezoelectric transformer.
  • the entire area is substantially divided into two near the center, and a thickness direction polarization part is formed on one of the two substantially divided areas, and an output electrode is provided on the end face of the other one of the areas.
  • a longitudinally polarized portion is formed.
  • the dimensional ratio of the piezoelectric transducer in the width direction and the length direction is changed from the position corresponding to 2Z4 wavelength (for example, 12 mm) to 3/4 wavelength (for example, 18 mm) in the length direction. It is configured so that the dimensional ratio is obtained by adding approximately 1 Z to each 4 wavelengths.
  • a thickness direction polarization portion and a length direction polarization portion are formed, la is an upper surface electrode of the thickness direction polarization portion, and lb is a lower surface electrode.
  • the backing electrodes are provided at both ends of the longitudinal dimension at a few percent of the entire length to 10 percent of the total length, so that high-power piezoelectric transformers are provided. Unnecessary vibration is suppressed by increasing the vibration intensity. Low power does not necessarily require a receding electrode.
  • the polarization in the thickness direction is completed by applying a high voltage in the thickness direction of the piezoelectric ceramic between the upper and lower electrodes 1a and 1b.
  • 1c is the output electrode applied to the end face of the piezoelectric ceramic.
  • Longitudinal polarization is completed by connecting the upper and lower electrodes la and lb, and applying a high voltage between the two connections and the output electrode 1c.
  • the length of electrode 1b is different, but may be the same.
  • a driving signal from a driving unit (not shown) is applied between a pair of thickness direction polarizing units 1a to 1b, and the driving signal is extracted from an output electrode 1c.
  • the discharge lamp is turned on by the output. Since this is well known, detailed description is omitted.
  • the length L force of the piezoelectric transducer 1 is 42 mm, the width W is 12 mm, and the thickness T force is 1.
  • Fig. 3 shows an example of the resonance characteristics of the thickness-polarized part on the input side at 2 mm.
  • a 1 is the resonance point of the primary resonance mode in the width direction and appears as a single-peak characteristic.
  • the electrical equivalent circuit of this resonance point is The characteristic is that the mechanical resonance system weighs the curve of the capacitor.
  • the capacitance of the electric arm of the equivalent circuit was measured at 500 to 450 PF.
  • the resonance impedance was measured at a value of 20 ohms or less.
  • FIG. 4 shows an example of the resonance characteristics of the longitudinal polarization section on the output side of the compression transformer 1 shown in FIG.
  • B 1 is the resonance point of the output-side longitudinal polarization section, which appears as a single-peak characteristic, and the electrode la of the thickness-direction polarization section that excites the primary mode in the width direction. Since the lb and lb counter poles are used as the lengthwise polarization part, the piezoelectric transformer is excited in the width direction. As an effect of this, it is possible to obtain resonance characteristics in which the resonance characteristics of the thickness-polarized portion on the input side and the resonance characteristics on the output side are substantially the same. In addition, the resonance impedance was measured at a value of 100 kohm or less.
  • the output electrode lc of the pressure transformer 1 shown in FIG. 1 is divided into, for example, three portions at a position near the center in the length direction to form a minute electrode portion.
  • this electrode portion as an output electrode, the electric capacity of the longitudinally polarized portion can be reduced to a small value.
  • the resonance frequency of the input section can be shifted to a frequency higher than the original frequency value. Therefore, the resonance frequency of the thickness direction polarization section on the input side and the length of the output side can be arbitrarily determined.
  • the driving frequency of the longitudinally polarized portion that matches the inductive region between the resonance frequency and the antiresonance frequency is indicated by a mark in FIG.
  • the piezoelectric transformer 1 shown in Fig. 1 is formed on the surface when the piezoelectric ceramic is molded with a mold or the like and fired at a high temperature of about 130 ° C.
  • an electrode of the thickness direction polarization portion, an electrode of the length direction polarization portion, and the like may be provided on the skin (skin layer) generated during firing.
  • the stress at the skin portion is increased, the mechanical strength of the piezoelectric transformer during vibration is increased, and an effect of suppressing unnecessary vibration components generated at high power is obtained.
  • the piezoelectric ceramic C ′ has a radius of 30 m ⁇ ! It is configured in a sector shape of about 100 mm and is parallel to one side (or arc) that has one of the longer dimensions of the length and width of the sector-shaped piezoelectric ceramic. In the vicinity of the central part, the entire area is roughly divided into two, and the thickness direction polarization parts 2a and 2b are formed on one of the two substantially divided surfaces, and the output electrode is formed on the end face of the other one area.
  • the piezoelectric transformer 2 having the lengthwise polarization part, the low order secondary vibration in the length direction of several KHz to 10 KHz is largely suppressed.
  • FIG. 5 shows a configuration of a piezoelectric drive assembly 2 ′ for parallel drive as another embodiment of the present invention.
  • the piezoelectric transformer assembly 2 ′ of the present embodiment is configured by electrically connecting a plurality of the piezoelectric transformers 1 shown in FIG. 1 in parallel.
  • This piezoelectric transformer uses the thickness direction polarization parts 2a to 2b and 2a 'to 2b' as the input part, and the electrodes 2c and 2c 'of the adjacent lengthwise polarization part as the output part.
  • a high voltage is obtained by using it.
  • a buffer band of several millimeters is provided between the two sets of piezoelectric transformers to reduce destruction such as polarization.
  • the combination of two pairs of piezoelectric drive assemblies 2 ′ for parallel driving shown in Fig. 5 increases the input current and output voltage by 4 to 6 times, and furthermore, combines 3 pairs. 6 to 9 times.
  • an arbitrary output can be obtained by changing the number of combinations of the parallel driving piezoelectric transformers shown in FIG.
  • Fig. 6 shows how to take out the signal lines of the piezoelectric transformer 1 shown in Fig. 1 or the piezoelectric transformer 2 shown in Fig. 2, and how to reinforce the piezoelectric transformer. And fixing method etc. are shown together. Since the piezoelectric transformer according to the present invention is vibrated in the primary mode in the width direction mode of the strong contour vibration, it is located closer to the center of the electrodes 1 a and 1 b on the input side of the piezoelectric transformer 1. The end of the fine wire 3 or 4 such as a small coil panel or tin plated wire is connected to the conductive paste or the other end of the vibration in the primary vibration mode in the width direction.
  • each fine wire should be fixed to the printed wiring board (not shown) by gluing it to the surface of the input electrodes 1a and 1b with soldering or baking silver. According to The combination of taking out signal lines and reinforcing and fixing the piezoelectric transformer 1 is provided. Also, since the output signal is taken out from the position where the vibration displacement is large using the thin wire 5, it is taken out along the element or as an example of the taking out method that guarantees the flexibility of the thin wire 5.
  • the thin wire is bent by providing a curved portion 5a near the fixing position, and the tip of the fine wire 5 is fixed to a printed wiring board or the like, two fulcrums are apparently formed, so the spring constant changes. As a result, we were able to improve the reliability for thousands of hours.
  • the thin wire 3 extends to the node of the vibration in the primary vibration mode in the width direction of the rectangular thin plate-shaped piezoelectric transformer 1 shown in Fig. 1 and extends over the entire length in the longitudinal direction of the piezoelectric transformer.
  • the effect of greatly suppressing low-order sub-vibrations in the longitudinal direction of several kHz to several ten kHz can be suppressed, and unnecessary vibration when a high voltage is applied is suppressed. .
  • the mechanical strength of the piezoelectric transformer can be increased, and high voltage output and large current output can be realized with low input. It also has the effect of eliminating the generation of abnormal noise at high power.
  • the thin wire may be fixed to one side or both sides. In the fan-shaped piezoelectric transformer 2 shown in FIG. 2, a thin wire can be similarly fixed.
  • the sub-resonance near the resonance point and the modulation that occurs at the time of hyper This has the effect of eliminating the occurrence of abnormal noise.
  • the piezoelectric transformer of the present invention assumes various actual loads such as a discharge tube and a strobe light source, it is necessary to adjust the output impedance of the piezoelectric transformer according to the load. There is. If the output impedance of the piezoelectric transformer is sufficiently lower than the input impedance of the actual load to be driven, the piezoelectric transformer side will be pulled by the load and the characteristics will deteriorate. It does not mean that the characteristics of the above are not exhibited. Therefore, since the drive of the load does not become impossible, the device has a wide application range.
  • a longitudinally polarized portion and an output portion on the output side are configured using a primary resonance mode in the width direction of the piezoelectric transformer and a counter electrode of an excitation electrode in the primary mode. Therefore, the input / output resonance frequency can be obtained as a resonance frequency that is substantially matched.
  • the impedance of the output section is high due to the large difference between the input and output resonant frequencies, so that only about tens or hundreds of milliamps can be input at 12 V.
  • the input current can input a relatively large current of several hundred milliamps in the piezoelectric transformer of the present invention.
  • This piezoelectric transformer is constructed as shown in Fig. 1 and Fig. 2, and it becomes structurally strong by increasing the area of the boundary between the input and output sections several times. As a result, the squealing phenomenon associated with high power excitation was alleviated and eliminated, and both the input current and the output voltage increased by two to three times.
  • the input and output resonance frequencies are made to substantially match by applying the contour mode width direction vibration mode which has a high Q value of the piezoelectric trans- former and provides strong vibration characteristics.
  • Output impedance should be low impedance. This has the effect of simultaneously realizing a high voltage of 1 to 1 OkV and a large output current of 1 to 1 OmA.
  • the input portion and the output portion of the fan-shaped or rectangular thin plate-shaped piezoelectric transformer are divided into two portions in the longitudinal direction at the central portion in the longitudinal direction. Since the actual size of the boundary between the longitudinally polarized portions has increased several times, the stress near the boundary between the thicknesswise polarized portion and the longitudinally polarized portion has the maximum value, as in the conventional piezoelectric transformer. The fatal drawback of breaking at the indicated position has been eliminated.
  • the output impedance of the piezoelectric transformer can be arbitrarily set with a low impedance of about 500 ⁇ to 100 k ⁇ . Because the glance is adjustable, the characteristics of the piezoelectric transformer are not degraded by the input impedance of the actual load, and the energy transmission efficiency can be dramatically increased. In addition, by configuring the piezoelectric transformer with the thickness direction polarization portion and the length direction polarization portion facing each other, there is also an effect that the bending vibration component is suppressed and the power can be increased.
  • the piezoelectric transformer is reinforced with skin layers and nodes that have no vibration loss in the longitudinal direction, and the piezoelectric transformers are electrically connected in parallel to form a piezoelectric transducer assembly.
  • the strength and output that were insufficient with a single piezoelectric transformer were increased, and unnecessary vibration was suppressed.As a result, heat generation could be minimized, and high power could be achieved. Therefore, there is an effect that the generated noise can be eliminated.
  • the piezoelectric transformer according to the present invention is capable of lighting a cold cathode discharge lamp. It is useful as a translator for equipment, and particularly suitable for equipment using high voltage generation such as copiers, static eliminators, ozone generators and flyback transformers. .

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

L'invention porte sur un transformateur piézo-électrique comprenant des sections de polarisation dans le sens de la longueur (1c, 2c, 2c') et dans le sens de l'épaisseur (1a, 1b, 2a, 2a', 2b, 2b') qui comportent une céramique piézo-électrique (C, C') dans laquelle les courbes de résonance dans le sens de la longueur et de la largeur sont établies sensiblement en concordance l'une avec l'autre. On renforce la résistance mécanique de ce transformateur piézo-électrique à l'aide des parties nodales de celui-ci, tandis que l'on constitue un assemblage de transformateur piézo-électrique (2') en montant ces transformateurs électriquement en parallèle.
PCT/JP1996/000904 1995-04-05 1996-04-01 Transformateur piezo-electrique WO1996031910A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP7/116267 1995-04-05
JP7116267A JPH08279632A (ja) 1995-04-05 1995-04-05 圧電トランス
JP7145113A JPH08306983A (ja) 1995-05-08 1995-05-08 圧電トランス
JP7/145113 1995-05-08

Publications (1)

Publication Number Publication Date
WO1996031910A1 true WO1996031910A1 (fr) 1996-10-10

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PCT/JP1996/000904 WO1996031910A1 (fr) 1995-04-05 1996-04-01 Transformateur piezo-electrique

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WO (1) WO1996031910A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS479365U (fr) * 1971-02-24 1972-10-04
JPS502269U (fr) * 1973-05-08 1975-01-10
JPH06177451A (ja) * 1992-12-08 1994-06-24 Nec Corp 圧電トランス及びその駆動方法
JPH0786658A (ja) * 1993-09-09 1995-03-31 Tamura Seisakusho Co Ltd 圧電トランス
JPH07221359A (ja) * 1994-02-07 1995-08-18 West Electric Co Ltd 圧電トランス

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS479365U (fr) * 1971-02-24 1972-10-04
JPS502269U (fr) * 1973-05-08 1975-01-10
JPH06177451A (ja) * 1992-12-08 1994-06-24 Nec Corp 圧電トランス及びその駆動方法
JPH0786658A (ja) * 1993-09-09 1995-03-31 Tamura Seisakusho Co Ltd 圧電トランス
JPH07221359A (ja) * 1994-02-07 1995-08-18 West Electric Co Ltd 圧電トランス

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