Patent Grant
6856071
1. Field of the Invention
The invention relates to a piezoelectric transducer, more particularly to a piezoelectric transducer module having interconnected transducer units.
2. Description of the Related Art
A transducer is a device that converts energy from one form to another. Transducers are commonly used for transformation of electrical energy into mechanical energy, and are extensively applied in the fields of electronics, electrical, mechanical and physics. Transducers for acoustic applications are commonly found in buzzers, earphones, microphones, speakers, etc.
Presently, piezoelectric material is commonly used as a basic component of transducers. When the piezoelectric material is subjected to a voltage drop, it mechanically deforms. Examples of materials that exhibit piezoelectric behavior include quartz, Rochelle salt, lead titanate zirconate cermics, barium titanate, and polyvinylidene fluoride.
In U.S. Pat. No. 6,323,583, there is disclosed a piezoelectric bending transducer that includes a flat, electrically conductive supporting body having piezoelectrically active coatings on both sides. The piezoelectrically active coatings are omitted from one end of the supporting body, which is fixed in a connector base. Each of the coatings and the supporting body are electrically connected to a plug-in contact that includes an electrically conductive elastomer in a cavity in the connector base for accepting a contact pin that deforms the elastomer when the contact pin is inserted thereinto. The contact pins are adapted to be connected to an electrical signal source. This arrangement is particularly adapted for incorporation into a transducer module with transducers secured adjacent to each other in a common connector base.
Although the transducer in the aforesaid patent dispenses with the bonding of contact wires as required in the prior art of
Therefore, the object of the present invention is to provide a piezoelectric transducer module that is relatively easy to manufacture and assemble, that can be produced with minimal material waste, and that includes a plurality of interconnected transducer units.
According to the present invention, a piezoelectric transducer module comprises:
first and second transducer units, each of which includes a conductive substrate portion that extends in a first direction and that has first and second surfaces opposite to each other in a second direction transverse to the first direction, at least one of the first and second surfaces having a piezoelectrically active coating coated thereon, the first and second transducer units being spaced apart from each other in the second direction; and
a connecting unit extending in the second direction and having opposite ends connected to the substrate portions of the first and second transducer units, respectively.
The substrate portions of the first and second transducer units and the connecting unit are formed from a unitary conductive plate that is folded at junctions of the connecting unit and the substrate portions of the first and second transducer units.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
Referring to
The connecting unit 723 extends in the second direction and has opposite ends 725 connected to the substrate portions 722 of the first and second transducer units 727, respectively. The connecting unit 723 is free of the piezoelectrically active coating 724.
The substrate portions 722 of the first and second transducer units 727, and the connecting unit 723 are formed from a unitary conductive plate 721. The conductive plate 721 is folded at the junctions of the connecting unit 723 and the substrate portions 722 of the first and second transducer units 727 to form a generally c-shaped structure.
The piezoelectric transducer module 7 further includes a set of contact wires 700, each of which is bonded to a respective one of the piezoelectrically active coatings 724 on the substrate portions 722 of the first and second transducer units 727, and each of which is adapted to be connected electrically to an electrical signal source (not shown). A contact wire 701 is also bonded to the connecting unit 723 and is adapted to be connected electrically to the electrical signal source.
With further reference to
In the first preferred embodiment, a pair of transducer units 727 can be constructed at one time by pressing or stamping a metal sheet to form the conductive plate 721 having the desired shape, followed by coating the substrate portions 722 with the piezoelectrically active coatings 724. Moreover, since the connecting unit 723 and the substrate portion 722 are formed from a unitary conductive plate 721, a single contact wire 701 can be bonded on the connecting unit 723 without the need for etching the piezoelectrically active coatings 724 on the substrate portions 722.
The piezoelectric transducer module of this embodiment further includes an insulating support member 81. The support member 81 is formed by injection molding directly on the transducer units 827 and the connecting unit 823, with the contact segment 829 extending outwardly of the support member 81.
The piezoelectric transducer module further includes an insulating support member 91 that encloses the connecting unit 923 and the contact member 92 and that has a spacer portion 912 disposed between the first and second transducer units 927, and a pair of securing portions 911, each of which secures a respective one of the first and second transducer units 927 on the spacer portion 912. Preferably, the support member 91 is formed by injection molding.
The support member 91 is provided with a set of contact plates 913 on the spacer portion 912 and the securing portions 911. The contact plates 913 establish electrical contact with the piezoelectrically active coatings 924 on the substrate portions 922 of the first and second transducer units 927, respectively, and are adapted to be connected electrically to the electrical signal source. The support member 91 is further provided with a contact plate 914 for establishing electrical contact with the connecting unit 923. The contact plate 914 is adapted to be connected electrically to the electrical signal source.
The second connecting unit 925 extends in the second direction and has opposite ends connected to the substrate portions 922 of the second and third transducer units 927, respectively. The second connecting unit 925 is spaced apart from the first connecting unit 923 in the first direction.
The piezoelectric transducer module further includes an insulating support member 91 that has a first spacer portion 912 disposed between the first and second transducer units 927, a second spacer portion 915 disposed between the second and third transducer units 927, and a pair of securing portions 911, each of which secures a respective one of the first and third transducer units 927 on an adjacent one of the first and second spacer portions 912, 915.
The support member 91 is provided with additional contact plates 913 on the spacer portions 912, 915 and the securing portions 911. The contact plates 913 establish electrical contact with the piezoelectrically active coatings 924 on the substrate portions 922 of the first, second and third transducer units 927, respectively, and are adapted to be connected electrically to the electrical signal source. The support member 91 is further provided with a contact plate 914 for establishing electrical contact with the first connecting unit 923. The contact plate 914 is also adapted to be connected electrically to the electrical signal source.
In this embodiment, the complementing structures of the transducer units 927 and the support member 91 firmly secure the transducer units 927 in the support member 91. Moreover, since the connecting units 923, 925 are enclosed within the securing portions 911 of the support member 91, a contact wire cannot be bonded directly on the connecting units 923, 925. However, through the contact plate 914, the substrate portions 922 of the transducer units 927 can still be connected electrically to the electrical signal source.
From the above description, the piezoelectric transducer module 7, 8, 9 of this invention is formed from a unitary conductive plate 721 that is folded to produce transducer units 727, 827, 927. Each of the surfaces 726, 826, 926 of the substrate portion 722, 822, 922 of each of the transducer units 726, 826, 926 is then coated with the piezoelectrically active coatings 724, 824, 924. The arrangement as such simplifies the manufacturing procedure. Furthermore, the piezoelectrically active coatings 724, 824, 924 need not be etched to bond contact wires. This results in increased manufacturing efficiency and minimal material waste.
While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4220885 | Yamashita et al. | Sep 1980 | A |
| 4328442 | Tanaka et al. | May 1982 | A |
| 4876675 | Ogura et al. | Oct 1989 | A |
| 5049776 | Ogawa | Sep 1991 | A |
| 5804906 | Tsutsumi | Sep 1998 | A |
| 5811911 | Janker et al. | Sep 1998 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20040119379 A1 | Jun 2004 | US |
