Electro-acoustic transducer comprising an rfid circuit
Electro-acoustic transducer comprising an rfid circuit
USPTO Application #: 20070086605 Title: Electro-acoustic transducer comprising an rfid circuit
Abstract: In an electro-acoustic transducer (1), there are provided sound-generating means (38) of an annular form that surround an interior space (22), in which interior space (22) is housed an integrated circuit (31) by means of which a communication circuit (31B) of an RFID communication partner device (37) is formed. (end of abstract)
Electro-acoustic transducer comprising an rfid circuit description/claims
The Patent Description & Claims data below is from USPTO Patent Application 20070086605, Electro-acoustic transducer comprising an rfid circuit.
 The invention relates to an electro-acoustic transducer having sound-generating means and having a circuit unit, which circuit unit has a circuit substrate and at least one circuit component of a signal-processing circuit, which circuit component is mounted on the circuit substrate.
 An electro-acoustic transducer of the kind specified in the first paragraph above is known from patent document U.S. Pat. No. 6,243,472 B1. In the known transducer, a plurality of circuit components are provided on a carrier of the circuit unit, which carrier is in the form of a plate, said circuit components forming a transducer circuit that is used to process and act on signals that are to be fed and are fed to the sound-generating means. In connection with a transducer of this kind having a transducer circuit incorporated in the transducer, reference may be made to the international patent application having the application number PCT/IB03/03275, of 18 Jul. 2003 (PHAT020049 EP-P). In the known electro-acoustic transducers, the at least one circuit component forms a transducer circuit, which gives advantages in respect of the processing of the acoustic signal but, on the other hand, constitutes a limitation because a transducer of this kind is often used in devices in which additional functionalities are provided for which a known transducer does not provide any support.
 It is an object of the invention to remove the limitation identified above and to produce an improved electro-acoustic transducer.
 To achieve the object stated above, features in accordance with the invention are provided in an electro-acoustic transducer in accordance with the invention, thus enabling an electro-acoustic transducer in accordance with the invention to be characterized in the manner specified below, namely:
 An electro-acoustic transducer having sound-generating means and having a circuit unit, which circuit unit has a circuit substrate and at least one circuit component of a signal-processing circuit, which circuit component is mounted on the circuit substrate, wherein the sound-generating means are annular in form and surround an interior space, which interior space is accessible from outside the sound-generating means when the transducer is being manufactured and before the circuit unit is fitted, and wherein the at least one circuit component is arranged in the interior space in the sound-generating means and forms a communication circuit of a communication partner device for contactless communication.
 What is achieved by the making of the provisions in accordance with the invention is above all that an electro-acoustic transducer intended for an electro-acoustic device can, in addition, be used to produce a communication partner device belonging to this electro-acoustic device, which is of advantage for a solution that is as inexpensive and space-saving as possible and requires the smallest possible number of assembly steps. The provision of the features in accordance with the invention makes it possible, in a structurally simple way, to obtain a particularly space-saving design of electro-acoustic transducer having a inbuilt communication circuit of a communication partner device, because the at least one circuit component of the communication circuit, which component is mounted on the circuit substrate, is housed within the interior space in the sound-generating means and therefore does not take up any additional space.
 In an electro-acoustic transducer in accordance with the invention, a plurality of discrete circuit components may be provided on the circuit substrate to form a communication circuit. A communication circuit of this kind may also be produced by thin-film technology. It has however proved to be highly advantageous if only a single circuit component is provided that is formed by an integrated circuit connected to the circuit substrate, which integrated circuit forms the communication circuit. A particularly small and space-saving solution can be obtained in this way.
 In an embodiment having an integrated circuit, it has further proved to be highly advantageous if, in addition, the features claimed in claim 3 are provided. This means that the moving coil is advantageously used for two purposes. A solution of this kind is also advantageous in that it allows the electrically conductive connection between the moving coil and the communication circuit to be of a form that is as simple as possible.
 In an electro-acoustic transducer in accordance with the invention, in which the sound-generating means have a diaphragm, connecting contacts that extend in parallel to one another may be provided in point or strip form on a face of the circuit substrate that is remote from the diaphragm. It has however proved to be highly advantageous if four connecting contacts, each in the form of a sector of a circular annulus, are provided on a face of the circuit substrate remote from the diaphragm. An embodiment of this kind has been found to be particularly advantageous in practice.
 The circuit unit may, for example, be fastened in place by means of at least one screw. It has however proved to be highly advantageous if the circuit unit is arranged to be removable without the use of a separate tool. For this purpose, a latching connection or a bayonet-type connection may be provided between the circuit unit and another component part of the transducer. It is also possible for a press-fit of greater or lesser tightness to be provided between the circuit unit and another component part of the transducer.
 These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter, to which however the invention is not limited.
 In the drawings:
 FIG. 1 shows in a cross-section an electro-acoustic transducer according to one embodiment of the invention, which transducer is provided with a circuit unit.
 FIG. 2 shows in an oblique view from the rear the transducer according to FIG. 1, without the circuit unit.
 FIG. 3 shows in an oblique view from the rear the circuit unit of the transducer according to FIG. 1.
 FIG. 4 shows in an oblique view from the front the circuit unit of the transducer according to FIG. 1.
 FIG. 1 shows an electro-acoustic transducer 1, which is a loudspeaker 1 in the present case. The transducer 1 is of a form that is substantially symmetrical about its center and it has a transducer axis 2.
 The transducer 1 has a housing 3 of a cup-like form that is composed of metal 30 and that has an end-wall 4 and a side-wall 5, the end-wall 4 being provided with a circular raised portion 6 in which are provided openings (not shown) for the passage of sound, and there being four tabs 7, in the form of strips, that project from the side-wall 5 and extend in radial directions towards the transducer axis 2, by means of which tabs 7 the component parts of the transducer 1 that are housed in the housing 3 are secured in their axial positions. It is also possible for more than four such tabs 7 to be provided. The radial positions of the component parts of the transducer 1 that are housed in the housing 3 are fixed with the help of the side-wall 5. The height of the cup-like housing 3 in the direction in which the transducer axis 2 is oriented and in the region thereof is 3.2 mm. The diameter of the housing 3 in directions extending perpendicularly to the transducer axis 2 is 13.2 mm. The transducer 1 is thus a transducer that is of a particularly small form. The transducer 1 is intended for use in, for example, a mobile telephone and similar telecommunication devices, which devices are intended to be particularly small in form, which means that the components used in them, such as the transducer 1, also need to be particularly small in form and to take up only a small amount of space. Consequently, it is advantageous for a transducer 1 of this kind if its dimensions are smaller than those of known transducers even by only a few tenths of a millimeter.
 The transducer 1 contains a diaphragm 8 that is substantially U-shaped in its edge region 9, the U-shaped edge region 9 being connected to a ring 10, which ring 10 is connected to the diaphragm 8 when the diaphragm 8 is being manufactured and which ring 10 is used for transport purposes and also for assembly purposes. When the transducer 1 is being manufactured, the ring 10 plus the diaphragm 8 connected thereto is slid into the housing 3 parallel to the direction of the transducer axis 2, the tabs 7 not yet having been bent over of course but extending in a direction substantially parallel to the transducer axis 2. The diaphragm 8 has an intermediate region 11 that connects up with the U-shaped edge region 9, an annular fastening region 12 that connects up with the intermediate region 11 and a central region 13 that is situated inside the fastening region 12, which central region 13 is used to generate sound. For this purpose, the diaphragm 8 as a whole is arranged to be capable of oscillating parallel to the transducer axis 2.
 The transducer 1 also has a magnet system 14. The magnet system comprises a permanent magnet 15, a first yoke 16 that is in the form of a circular annulus and rests flat against the permanent magnet 15, and a second yoke 17 of L-shaped configuration in cross-section, of which second yoke 17 a first portion 18 of disc shape likewise rests flat against the permanent magnet 15 and a second portion 19 in the firm of a hollow cylinder projects from the-first portion 18 in a direction-parallel to the transducer axis 2; When the transducer 1 is being manufactured, the first yoke 16, then the permanent magnet 15 and then the second yoke 17 are slid into the housing 3 parallel to the direction of the transducer axis 2. Once the three parts 16, 15 and 17 of the magnet system have been slid into place, the tabs 7 on the housing 3 are bent over to the positions shown in FIGS. 1 and 2, as a result of which the diaphragm 8 and the magnet system 14 are then fixed in place. Between the free end of the second portion 19 of the second yoke 17 and the inner edge of the first yoke 16 is formed an air-gap 20 that is defined by the two parts of the magnet system, namely the first yoke 16 and the second yoke 17. The magnet system 14 has a boundary face 21 that is situated on the side remote from the diaphragm 8 and that forms the outside boundary of the magnet system 14, which boundary face 21 is formed by a face, in the form of a circular annulus, of the first portion 18 of the second yoke 17.
 The magnet system 14, a moving coil 29 and the diaphragm 8 form sound-generating means 38 of the transducer 1.
 As can be seen from FIGS. 1 and 2, the magnet system 14 is advantageously annular in form in the present case. Consequently, the sound-generating means 38 too are annular in form. The magnet system 14 surrounds an interior space 22, which interior space 22 is accessible, when the transducer 1 is being manufactured and before a circuit unit 23 is fitted (details of the form of which latter will be given below), from outside the magnet system 14 over the whole of its extent in directions lying perpendicular to the transducer axis 2 and has the transducer axis 2 passing through it In the present case, the annular form of the magnet system 14 and the sound-generating means 38 is defined as a circular annulus. The annular form may however also be of elliptical, rectangular or square configuration.
 Firmly held in the interior space 22 is a contact carrier 24, which contact carrier 24 is composed of plastics material and is intended to hold two moving-coil contacts 25, of which moving-coil contacts 25 only one, 25, can be seen in FIG. 1 due to the fact that the view is in cross-section. The moving-coil contacts 25 are connected to the contact carrier 24 by being molded into it. Each moving-coil contact 25 has a U-shaped portion 26, between the two side-members of which is clamped one end 27 of a moving-coil wire. Each moving-coil contact 25 has an L-shaped portion 28 that projects from one side-member of the U-shaped portion 26.
 The transducer 1 contains a moving coil 29, which moving coil 29 is arranged partly in the air-gap 20 and is connected to the diaphragm 8 in the latter's fastening region 12 by means of an adhesive-bonded joint (not shown). The moving coil 29 cooperates with the magnet system 14, there being fed to the moving coil 29 an electrical signal that represents a signal to be reproduced acoustically, as a result of which the moving coil 29 is caused to oscillate and the diaphragm 8 produces the signal that is to be reproduced acoustically. The electrical signal fed to the moving coil 29 has to be amplified, and may also need to have its signal waveform acted on if required, before it is fed to the moving coil 29. What is required for this is a transducer circuit 31A that is arranged to perform the requisite actions on the signal, in particular to amplify it.