Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2002-06-14
2004-12-21
Budd, Mark (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S348000
Reexamination Certificate
active
06833653
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a piezoelectric transformer device, a housing for the piezoelectric transformer, and a method of manufacturing them, and more particularly to a piezoelectric transformer device, a housing for the piezoelectric transformer, and a method of manufacturing them, in which the housing has integral lead frames resiliently protruded to contact input and output portions of the piezoelectric element, and is comprised of a pair of housing parts surrounding both sides of the piezoelectric transformer, and the lead frames are outwardly extended from the housing.
2. Description of the Prior Art
In general, piezoelectric transformers are widely used these days because the piezoelectric transformer can be reduced in its size and thickness as compared with a coil type transformer, and is characterized by high efficiency and insulation performance and incombustibility. Such piezoelectric transformers are used with inverters for back-lights of color liquid crystal displays and high voltage generating circuits. At the moment, products in which a back-light inverter of a color liquid crystal display is incorporated include notebooks, PDAs (Personal Digital Assistants), DVCs (Digital Video Cameras), DSCs (Digital Still Cameras), and high voltage generating circuits are used in dust collectors, air purifiers and ozone generators.
A construction and operating principles of a piezoelectric transformer will be described as follows. In the piezoelectric transformer which is known as a DC high voltage generating circuit, when a driving portion of the piezoelectric transformer is applied with its inherent resonant frequency, high voltage is induced at a vibrating portion by its piezoelectric effect. Although piezoelectric transformers can be classified into various kinds of piezoelectric transformers, a Rosenberg type piezoelectric transformer, which employs longitudinal vibration of a rectangular piezoelectric ceramic, is generally used.
FIG. 1
shows a construction of the Rosenberg type piezoelectric transformer. As shown in the drawing, an input portion
120
is symmetrically provided at its upper and lower surfaces with electrode faces
110
, and an output portion
130
is provided at its end surface with electrode faces
140
. The input portion
120
having the input electrodes
110
is polarized in the thickness (T) direction, and the output portion
130
having the output electrode is polarized in the lengthwise (L) direction. When the input electrode is applied with AC voltage corresponding to resonant frequency of the piezoelectric element, voltage is generated from the output electrode by piezoelectric effect and thus electric power is supplied to a load. That is, AC voltage applied to the input portion is converted to higher voltage at the output portion via ultrasonic mechanical vibration, thereby increasing voltage.
As illustrated in the above, a piezoelectric transformer comprises the input portion
120
and the output portion
130
. The input portion serves as a driving portion for converting input electrical energy into mechanical vibration energy, and includes input electrodes at its upper and lower surfaces. The output portion serves as a generating portion for converting the mechanical vibration energy into electrical energy, and includes the output electrode at its right end surface. When the input portion is applied with electric voltage, the input portion is mechanically vibrated. The mechanical vibration is transmitted to the output portion in the lengthwise direction and thus piezoelectric effect occurs due to the mechanical vibration, thereby generating electric voltage. A ratio of input voltage to output voltage is determined by shapes of input portion and output portion of a piezoelectric transformer.
FIG. 2
shows a shape and electrode patterns of a single plate type &lgr; mode piezoelectric transformer. As shown in the drawing, an input portion of the piezoelectric transformer is printed with input electrodes
210
at its upper and lower surface, and an output portion of the piezoelectric transformer is provided at its end with a “U”-shaped output electrode
220
.
A conventional housing for accommodating such a piezoelectric transformer is illustrated in
FIGS. 3 and 4
. A piezoelectric transformer and a housing shown in
FIGS. 3 and 4
are disclosed in Japanese Patent Laid-Open No. 8-32135. Solder wires
305
and
306
are connected to the center of node supporting points of an input portion and an output portion of the &lgr; mode piezoelectric transformer
301
and then connected to a plastic housing
307
. The housing is provided with holding protrusions
308
at 4 positions, which are intended to hold the solder wires
305
and
306
extended from the input portion and the output portion. The piezoelectric transformer
301
is applied with adhesive and then attached in the housing
307
.
Such a housing for a conventional piezoelectric transformer has a simple construction. However, since both electrode portions of a piezoelectric transformer are soldered with solder wires
305
and
306
and the piezoelectric transformer is mounted on a PCB
310
, mass production and quality improvement are difficult due to connection of wires and manufacturing cost is increased due to breakage of wires and an increased number of procedures.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a contact structure of a piezoelectric transformer and a housing in which lead frames are integrally formed with the housing to allow the lead frames to easily contact the piezoelectric transformer and to prevent breakage of the contact.
Another object of the present invention is to provide a housing, which has lead frames, adapted to resiliently support a piezoelectric transformer to improve structural stability and operational effect.
In order to accomplish the above object, the present invention provides a housing for receiving a piezoelectric transformer having a voltage input portion and a voltage output portion, both of which include a plurality of electrodes, including an upper housing part having at least two first lead frames which are protruded at ends thereof to resiliently come into contact with a point of the input portion and a point of the output portion of an upper surface of the piezoelectric transformer. Furthermore, the housing includes a lower housing part having at least two second lead frames which are protruded at ends thereof to resiliently come into contact with a point of the input portion and a point of the output portion of a lower surface of the piezoelectric transformer. The first and second lead frames are outwardly extended from the upper and lower housing parts, and the piezoelectric transformer is received in the upper and lower housing parts such that the piezoelectric transformer is resiliently supported by the first and second lead frames.
According to another embodiment, the present invention provides a housing for receiving a piezoelectric transformer having upper and lower surfaces and side surfaces connecting the upper and lower surfaces, and having a voltage input portion and a voltage output portion, both of which include a plurality of electrodes, including an upper housing part surrounding the upper surface and the side surfaces of the piezoelectric transformer, and having I) at least two first openings formed thereon, and II) at least two first lead frames made of conductive elastic material, each of which is extended from one of the side surfaces into the inside of the first opening of the upper housing part and is protruded at the extended end to be in contact with at least one electrode of the piezoelectric transformer. Furthermore, the housing includes a lower housing part surrounding the lower surface and the side surfaces of the piezoelectric transformer, and having i) at least two second openings formed thereon, and ii) at leas
Hyun Bu Whan
Lee Wook Hee
Na Gi Lyong
Budd Mark
Lowe Hauptman & Gilman & Berner LLP
Samsung Electro-Mechanics Co. Ltd.
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