JPH0727173U - High voltage generator - Google Patents

Abstract

(57) [Abstract] [Purpose] To manufacture a high-voltage generator at low cost using a piezoelectric transformer that extracts the optimum output voltage for each set model used. [Structure] A piezoelectric element is supported in an opening of a substrate, an output take-out portion that comes into contact with an arbitrary position of the piezoelectric element output portion is provided, and a metal piece for sandwiching the output take-out portion with the substrate is provided on the substrate. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high voltage generator using a piezoelectric transformer.

[0002]

[Prior art]

 A high voltage generator using a piezoelectric transformer is known to be suitable for supplying a high voltage to a high impedance load, since it can obtain a large boost ratio with a simple structure without requiring windings. There is. Further, since it uses a piezoelectric element made of ceramic, it is nonflammable, and is useful for a plain paper copy (PPC), a laser beam printer (LBP), a backlight of a liquid crystal device, and the like.

FIG. 3 shows a conventional high voltage generator using a piezoelectric transformer. In the rectangular piezoelectric element 1, one half of the rectangular piezoelectric element 1 in the longitudinal direction serves as the input portion 2 in the thickness direction (arrow P), and the other half of the rectangular piezoelectric element 1 serves as the output portion 3 in the longitudinal direction (arrow Q). ) Is polarized. A pair of input electrodes 4A and 4B are formed on the two surfaces of the input section 2 facing each other in the thickness direction, and an output electrode 5 is formed on the end surface of the output section 3 in the longitudinal direction. The input electrodes 4A and 4B are connected to a drive signal source 6 including an AC power supply Vi and a DC power supply Eb, and a lead wire 7 is connected to the output electrode 5. The boosted output voltage is taken out between the lead wire 7 and the ground.

Next, the operation of the high voltage generator using this piezoelectric transformer will be described. When an AC voltage is applied between the input electrodes 4A and 4B by the drive signal power source 6, the piezoelectric element 1 vibrates due to the piezoelectric effect. This vibration is divided into a traveling wave and a backward wave, propagates along the length direction of the rectangular piezoelectric element 1 toward the right end and the left end, respectively, and is reflected by the end faces of the rectangular piezoelectric element 1. Come and go The rectangular piezoelectric element 1 resonates when a specific frequency determined by the length of the rectangular piezoelectric element 1 and the frequency constant peculiar to the material is applied, and a standing wave is generated. As this condition, a half-wavelength resonance vibration mode and a full-wavelength resonance vibration mode are known. As a result, in the output section 3 of the rectangular-shaped piezoelectric element 1, an electric field distribution is created by the piezoelectric effect due to the amplified strain, and a boosted output voltage is obtained at the output electrode 5.

In the output section 3, the generated voltage linearly increases from the ends of the input electrodes 4 A and 4 B toward the output electrode 5, and reaches the maximum voltage at the output electrode 5.

[0006]

[Problems to be solved by the device]

 Conventionally, the value of the boosted voltage is changed by adjusting the drive frequency of the AC power supply Vi of the drive signal source 6 or the DC power supply Eb. However, in order to adjust the drive frequency of the AC power supply Vi, a frequency variable mechanism using a coil or a capacitor for determining the oscillation frequency is required, which increases the cost. Further, when the power supply voltage Eb is adjusted, heat loss is involved and heat radiation is taken into consideration, which is not suitable for a compact design.

Therefore, an object of the present invention is to provide at low cost a high voltage generator using a piezoelectric transformer capable of obtaining an optimum output voltage for each set model used.

[0008]

[Means for Solving the Problems]

 The present invention is configured as follows to achieve the above object.

In a high voltage generation device including a piezoelectric element including an input section that is polarized in the thickness direction and provided with a pair of input electrodes facing each other on the upper and lower surfaces, and an output section that is polarized in the direction orthogonal to the thickness direction, In this configuration, a conductive output voltage extracting portion is provided in the part, and the output voltage extracting portion is sandwiched between a flat plate spring provided on the printed circuit board and the printed circuit board.

[0010]

[Action]

 In a high voltage generator using a piezoelectric transformer, a conductive material that is slidable is brought into contact with the output portion of a rectangular piezoelectric element to extract the output voltage at that location.

[0011]

【Example】

 FIG. 1 illustrates an exploded perspective view of an on-board type high voltage generator using the high voltage generator using the piezoelectric transformer of the present invention. Since the rectangular piezoelectric element is the same as that of the conventional example, its description is omitted and the same number as that of the conventional example is used.

The on-board type high voltage generator includes a rectangular piezoelectric element 1, a printed board 8, a fixing jig 9 for fixing the rectangular piezoelectric element 1 to the printed board 8, and a rectangular piezoelectric element 1. An output voltage extracting unit 10 for extracting the boosted output voltage by fitting it to the output unit 3, and a metal piece 11 for connecting the output voltage extracting unit 10 and a circuit (not shown) of the printed circuit board 8 to each other. Composed of.

Components (not shown) that constitute, for example, an oscillation circuit, a control circuit, a rectifying circuit, etc. are mounted on the printed circuit board 8, and the rectangular piezoelectric element 1 is fixed by a fixing jig 9. An opening 12 is provided for locking.

The fixing jig 9 is made of a material such as rubber having an insulating property and a high elastic modulus. The fixing jig 9 is provided with a space 13 into which the input portion 2 of the rectangular-shaped piezoelectric element 1 is fitted, penetrating opposite side surfaces of the fixing jig 9. Further, on both sides of the fixing jig 9, in order to engage with the printed board 8, grooves 14 having the same thickness as the printed board 8 are provided in a direction orthogonal to the thickness direction.

A space 15 into which the output portion 3 of the rectangular piezoelectric element 1 is fitted is provided in the output voltage extracting portion 10 so as to penetrate through opposite side surfaces of the output voltage extracting portion 10. Further, a tongue piece 16 for contacting the metal piece 11 is provided integrally with the output voltage extracting portion 10 at one end of the member of the output voltage extracting portion 10. The output voltage extraction unit 10 has conductivity, has a large friction coefficient to prevent deviation from the set output voltage extraction position, and hinders the movement of the rectangular piezoelectric element 1 when resonating. A material such as a conductive rubber is preferable because it requires flexibility or the like to follow its movement without doing so.

The metal piece 11 is made of a material such as phosphor bronze, and is made of a flat spring having a length substantially the same as the length of the output section 3. The output voltage extracting unit 10 can be slid on the output unit 3 in order to extract the optimum output voltage for each set model used. When fixing the metal piece 11 to the printed circuit board 8, the claw 11A provided on the metal piece 11 is inserted into the opening 17 provided on the substrate 8 on the assumption that the metal piece 11 can be securely fixed to the printed circuit board 8. Any method such as post-bending and fastening or screwing may be used.

As shown in FIG. 2, the on-board type high voltage generator has the fixing jig 9 inserted into the input portion 2 of the rectangular piezoelectric element 1 and the output voltage extracting portion 10 inserted into the output portion 3 and then the fixing jig. The printed circuit board 8 is locked in the groove 14 of the groove 9. As a result, the rectangular piezoelectric element 1 is held in the opening 12 of the printed board 8 without contacting the printed board 8. Moreover, only the tongue piece 16 of the output voltage extracting portion 10 contacts the printed circuit board 8.

The tongue piece 16 of the output voltage take-out section 10 is clamped and fixed between the metal piece 11 and the printed circuit board 8 at a predetermined position on the output section 3, and the optimum output voltage is taken out for each set model used. Be done.

When the output voltage is taken out from the output voltage take-out section 10, instead of the metal piece 11, the tongue piece 16 may be connected to the circuit on the printed circuit board 8 and a lead wire.

[0020]

[Effect of device]

 Since the present invention is configured as described above, it has the following effects. By sliding the output voltage extracting section 10 on the output section 3 of the rectangular piezoelectric element 1, an arbitrary boosted output voltage can be extracted. Therefore, it is not necessary to design a high voltage generator using a piezoelectric transformer for each set used conventionally.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an onboard high voltage generator according to the present invention.

FIG. 2 is an assembly view of an onboard high voltage generator according to the present invention.

FIG. 3 is a high voltage generator using a conventional piezoelectric transformer.

[Explanation of symbols]

 1 Rectangular Piezoelectric Element 2 Input Section 3 Output Section 4A, 4B Input Electrode 5 Output Electrode 6 Driving Power Supply 8 Printed Circuit Board 9 Fixing Jig 10 Output Voltage Extraction Section 11 Metal Piece 16 Tongue Piece

Claims (2)

[Scope of utility model registration request] 1. A high voltage generator comprising a piezoelectric element comprising an input section provided with a pair of input electrodes polarized in the thickness direction and opposed to the upper and lower surfaces, and an output section polarized in the direction orthogonal to the thickness direction. A high voltage generator characterized in that a conductive output voltage extracting portion is provided in the output portion. 2. The high voltage generator according to claim 1, wherein the output voltage extracting portion is sandwiched between a plate spring provided on the printed board and the printed board.