The patent's assignee for patent number 8644114 is
News editors obtained the following quote from the background information supplied by the inventors: "The invention relates to a signal transmitter device comprising an electrical acoustic signal transmitter having a piezoceramic disk on a metal membrane, said signal transmitter also being known as a piezo-buzzer, for example.
"A similar signal transmitter device is known from U.S. Pat. No. 4,841,493, for example. In that case, the signal transmitter lies over an opening in a printed circuit board or in a carrier, with the metal membrane facing towards the carrier, while the piezoceramic disk faces away therefrom. Similar signal transmitters are also known and available as surface mounted device ('SMD') components, wherein corresponding electrical connections are then provided on the carrier or a resonator housing."
As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "An object of the invention is to provide a signal transmitter device as disclosed above which can be used to solve problems in the prior art and, in particular, to provide a practical and functionally entirely satisfactory construction that is suitable for simple and reliable mounting.
"This object is achieved in one embodiment by means of a signal transmitter device as claimed herein. Advantageous and preferred configurations of the invention are the subject matter of the further claims and are explained in greater detail below. The wording of the claims is incorporated by express reference in the content of the description.
"The printed circuit board or a corresponding carrier for the signal transmitter has an opening in the region of the piezoceramic disk or the metal membrane. Said opening serves for acoustic amplification and/or to enable the signal transmitter to oscillate better or even oscillate in the first place. In this embodiment, the metal membrane substantially extends over the opening in order to bear on the printed circuit board in its edge region. Thus, the metal membrane and in particular the signal transmitter can also be fixed to the printed circuit board.
"According to one embodiment of the invention, the piezoceramic disk is arranged on the metal membrane, or the signal transmitter is arranged on the printed circuit board, in such a way that the piezoceramic disk faces toward the opening and advantageously even substantially projects into the opening, and is at least arranged in the region thereof. In the edge region of the opening, a projecting contact projection is provided for the electrical contact-connection to the signal transmitter, wherein the contact projection proceeds from the edge region or from the inner edge. Advantageously, the contact projection projects from the printed circuit board or the latter forms it.
"In this way, this achieves a good mechanical or acoustic functionality of the signal transmitter in interaction with the opening in the printed circuit board or the carrier. Further, however, the arrangement of the signal transmitter in such a way that the piezoceramic disk faces toward the opening or the printed circuit board makes it possible to facilitate and improve the electrical contact-connection thereto, that is to say both to the metal membrane and to the piezoceramic disk. This will be explained in greater detail below.
"Advantageously, the piezoceramic can also be embodied as a thin layer, for example having a thickness of approximately 30 .mu.m to 150 .mu.m, particularly advantageously approximately 50 .mu.m, wherein it can be printed or vapor-deposited onto the metal membrane. However, it will still be regarded as a disk hereinafter.
"In another embodiment of the invention, the metal membrane can substantially cover, particularly advantageously, the opening in the printed circuit board. It can rest or bear on a ring electrode that lies at the opening or runs around the edge region thereof. In this case, the ring electrode can run around substantially or even completely. It can be embodied as a conventional metal layer or metallization and make electrical contact with the metal membrane, for example by soldering, as an electrical connection to the signal transmitter.
"In another embodiment of the invention, the ring electrode can have a plated-through hole through the printed circuit board in at least one location. Thus, the ring electrode can be connected to an electrical connection or a conductor track on the other side of the printed circuit board, either as external connection possibility or as interconnection with other components or circuit parts on the printed circuit board. Such a plated-through hole through a printed circuit board or a corresponding carrier does not pose a problem technically and is sufficiently known to the person skilled in the art, for example, as a through hole with an electrically conductive coating on the inner wall of the through hole.
"The contact projection for the electrical contact-connection to the signal transmitter is advantageously formed from the printed circuit board, or projects as an integral part of it from the inner edge of the printed circuit board into the opening. It can be advantageously embodied substantially in the form of a bar or a nose-piece, that is to say, in an elongate fashion. In particular it has an approximately uniform width. Its length can be as desired, in principle. Thus, for example, it can also virtually bridge the majority of the opening. Advantageously, the length of the contact projection is approximately 10% to 50% of the diameter of the opening. In this embodiment, it can run substantially straight and in a direction toward a midpoint of the opening. In its end region, the contact projection can have a contact zone or a contact point by which it bears against the piezoceramic disk. The electrical contact-connection thereto is therefore effected via a bearing contact. The latter can possibly be improved with an electrically conductive adhesive or a soldered joint, but this is not necessary in all embodiments.
"By means of the contact projection, particularly if it is embodied according to one of the abovementioned possibilities, it is therefore possible to reach the piezoceramic disk from the edge of the opening and thus from the printed circuit board directly, for the electrical contact-connection of said disk. Separate components such as contact bridges, contact arms to be fitted separately or the like, are not required, which has a very advantageous effect on the simplicity and reliability of mounting.
"For a reliable electric contact-connection even in the case of mechanical movement of the signal transmitter or mechanical tolerances, it may be provided, in particular by means of the abovementioned contact zone, that the contact projection and therefore also the contact zone bears against the piezoceramic disk with prestress or a certain force. By virtue of the elongate embodiment of the contact projection, the latter has certain elastic spring properties. Thus, the electrical contact is always ensured, even in the case of movement or oscillations of the signal transmitter.
"In a further embodiment of the invention, the electrical contact-connection to the piezoceramic disk can have a plated-through hole through the printed circuit board, which is led to a contact zone or a conductor track or an electrical connection on the other side of the printed circuit board. Consequently, in a manner similar to that described above for the contact-connection to the metal membrane, a plated-through hole can also be provided for the electrical connection to the piezoceramic disk. Particularly advantageously, the plated-through hole is provided very near or in the region of the electrical contact-connection to the piezoceramic disk, for example, actually in the contact projection itself or below the contact zone. Particularly advantageously, the plated-through hole is provided exactly at the location at which a contact zone or the like for bearing against the piezoceramic disk is also provided. This has the advantage that the remaining top side of the contact projection is then separated from a contact-connection, or a corresponding conductor track, and therefore does not entail any problems with regard to the fact that further toward the outside in the edge region of the opening the metal membrane of the signal transmitter is present or covers the contact projection. Thus, for the metal membrane, too, it is possible to provide an abovementioned ring electrode running completely around the opening. The holding projection extends within said ring electrode or it can also be provided on the holding projection, but at a distance from a plated-through hole or a contact zone to the piezoceramic disk, the electrical connection of which, specifically, is then effected on the other side of the printed circuit board. Consequently, overall both connections can also be provided on the other side of the printed circuit board by means of corresponding plated-through holes. They can then run alongside one another there without any problems.
"In an alternative embodiment of the invention, an electrical contact-connection on the contact projection to the piezoceramic disk can be formed without through-plating onto the other side. The contact-connection then runs on this side of the printed circuit board, along the contact projection outward with a conductor track from a contact zone on the contact projection for the piezoceramic disk to a remote electrical connection. For this purpose, it is possible to provide an insulating cover over said conductor track, at least in the region in which the metal membrane projecting beyond the piezoceramic disk also runs over said conductor track or projects beyond the latter. The insulating cover should cover the conductor track apart from the contact zone at least over the length of the contact projection and, for safety reasons, also project or protrude a little beyond the metal membrane. An insulating cover can be, for example, a soldering resist that is applied to the printed circuit board anyway, or some other coating. Alternatively, it can be a piece of adhesive film or the like.
"In order to increase the flexibility of the contact projection even further, since, as a result of soldering to the piezoceramic disk for the electrical contact-connection, said contact projection can be part of the oscillating system and exerts a certain damping, incisions into the printed circuit board can be provided on both sides of the contact projection. Thus, the contact projection is lengthened as it were, even though it does not project further into the opening. Said incisions can have between 50% and 300% of the free length of the contact projection within the opening, that is to say, form a lengthening that is significant under certain circumstances. These incisions can interrupt or disturb somewhat the formation of the abovementioned ring electrodes for the electrical contact-connection to the metal membrane, but in practice this is manifested only in the minimally shortened contact length or contact area thereof and is therefore not disturbing.
"The opening in the printed circuit board and the piezoceramic disk can have a substantially corresponding or identical form, and both can be particularly advantageously circular. In this case, the piezoceramic disk is preferably arranged concentrically with respect to the opening in the printed circuit board, even though usually it does not project into the latter, but rather runs somewhat above the plane of the printed circuit board.
"In a further embodiment of the invention, a drive circuit, preferably comprising a microcontroller, designed for driving the signal transmitter, can be provided on the printed circuit board or the carrier at a small distance from the opening. It can be arranged on the same side as the signal transmitter, for example, and a distance can be approximately of the order of magnitude of the diameter of the metal membrane. It is thus possible to provide an overall signal transmitter device which has a compact construction and can be produced easily. If the drive circuit is situated on the same side of the printed circuit board as the signal transmitter, then an electrical connection to the signal transmitter without the abovementioned plated-through holes is advantageously chosen, that is to say in particular with an insulating cover over a conductor track at the contact projection to the piezoceramic disk.
"In yet a further embodiment of the invention, a resonator housing can be provided in a conventional manner over the signal transmitter. It can be embodied as a Helmholtz resonator and can be advantageously arranged on the same side of the printed circuit board as the signal transmitter. It can be embodied as a plastic component which is pressed into corresponding recesses in the printed circuit board and then holds it there by clamping or in some other way.
"These and further features emerge not only from the claims but also from the description and the drawings, wherein the individual features can be realized in each case by themselves or as a plurality in the form of subcombinations in one or more embodiments of the invention and in other fields that can constitute advantageous and inherently protectable embodiments for which protection is claimed here. The subdivision of the application into individual sections and sub-headings does not restrict the general validity of the statements made hereunder."
For additional information on this patent, see: Fluhrer, Henry; Stuhr, Frank. Signal Transmitter Device Comprising an Electrical Acoustic Signal Transmitter. U.S. Patent Number 8644114, filed
Keywords for this news article include: Electronics, Circuit Board,
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