RO119055B1 - Vibration transducer and loudspeaker for using the same - Google Patents

Abstract

The invention relates to a vibration transducer and a speaker for its use. The vibration transducer (9) according to the invention is intended for use for the vibration of a radiant element (2), single front, comprising a motor coil assembly (13 and 18), whose coil (13) is rigidly fixed by a tubular part ( 18), the motor-coil assembly (13 and 18) being adapted for fixing on the respective face of the radiant element (2), it also comprising a magnetic assembly (15) containing polar parts, opposite, in disc form, the end of one of said polar parts, being adapted for positioning adjacent to the coil-motor assembly (13 and 18), while the end of the other polar piece contains a surrounding border (90), which is adapted to be arranged around the coil assembly -motor (13 and 18), in a position adjacent to it, the respective magnetic assembly (15) being adapted for fixing, with its central part, the radiating element (2), mentioned, which must be placed n vibration. à

Description

The invention relates to a vibration transducer and a diffuser for its use, the vibration transducer being intended for use within speakers such as those containing radiant acoustic elements in panel form.

It is known from the patent application GB-A-2262861 the solution for making a panel-shaped speaker, comprising:

- a radiant element in various ways, resonant, in the form of sandwich panel, forming a unitary cellular construction consisting of two film layers of a material, separated by a core highlighted by the cross-section of the cell construction, the panel having, independently of steering, a coefficient of resistance to bending (B) equal to the mass of the panel at power 3, per unit of surface (μ), of minimum value 10;

- a mounting device that supports the panel or secures it to a support body, freely and without cushioning;

- an electromechanical actuator device coupled to the panel and which is used to excite the resonant panel, radiant in various modes, in response to the application of an electrical signal corresponding to the working frequency band of the speaker.

In US Patent A-4506117, holder Multifonie, an electroacoustic transducer containing an inertial weight adapted to be fixed, rigidly, to its base plate on the panel is described so that it can be vibrated.

In order to achieve the present invention, elements of a certain type, structure and configuration are commonly obtained and / or in particular, by applying the knowledge from the publication of PCT patent application WO97 / 09842, whose applicant is the same as that of the patent application. PCT patent which was the basis for the opening of the national phase of the present patent application. Such elements have the capacity to maintain and propagate, through flexural waves, input vibration energy, in the operational area or areas which, as a rule, extend transversely on thickness, and not necessarily to the edges of the respective element or elements, being configured with or without anisotropy of flexural rigidity to have resonant type vibration components, advantageously distributed, in the respective or respective areas, for achieving acoustic coupling with the environment, having preferential locations or locations, predetermined, inside in that area, in order to dispose of a translator in the respective zone or areas, in particular in that part or operationally active or mobile parts thereof, effective in terms of acoustic vibration activity and in terms of signals, usually electrical, corresponding to the content acoustics of such activity v ibraţionale. In the publication of the mentioned PCT patent application WO97 / 09842, the uses of such elements are presented, within devices such as passive acoustic devices without a translator, such as, for example, for reverb, for acoustic filtration or for achieving acoustic harmony in -a space or in a room; and in acoustic devices active with the transducer, such as those in the very wide range of acoustic or speaker sources, when they are provided with input signals, to be converted into sound signal respectively, or as for example microphones when they are exposed to an audible signal to be converted to another signal.

The present invention relates to a vibration transducer, on the one hand, and on the other hand to a speaker for its use.

Elements of the above are known, such as, for example, radially distributed radiating elements, the characteristics of which are in accordance with the solution described in the aforementioned PCT patent application and / or in accordance with the specific features of the invention. from this description.

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The invention relates to a vibration transducer intended to excite a simple radiant element in front, having the ability to maintain and propagate, through the bending waves, vibrational input energy, in at least one active area that extends transversely on the thickness, for 50 a. had vibrating components of resonant type, distributed over the respective area, and to have preferential locations or locations, predetermined, within that area, for arranging in one of those locations or locations, a translator mounted integrally and exclusively, on said radiant element , to determine the vibration of said radiant element, so that it enters the resonance, thus forming an acoustic emitter 55 which generates acoustic radiation when it resonates, containing a motor coil assembly having a coil rigidly fixed to a tubular part, the assembly motor coil being adapted to be fixed on their face ment, and a magnetic assembly containing two opposing disc-shaped parts in place of poles, the periphery of one of the two pieces being intended to be located within the motor coil assembly, in a position adjacent to it, and the periphery of the other piece contains an edge adapted to surround the motor coil assembly, also in an adjacent position, and in which the magnetic assembly is intended to be fixed in the center of said element to be vibrated.

Some fastening means ensure that the magnetic assembly is fastened to the element. The fasteners may contain a fastener adapted to be engaged in a cavity of the member. The fixing device may contain a spacer for separating the periphery of the polar parts from the respective element. The vibration transducer may contain, in addition, a motor coil assembly and a magnetic assembly adapted for mounting on the opposite sides of the respective element, and some means for attaching the centers of the magnetic assemblies together for a push / pull operation. Thus, the fixing device 70 may have the ends at the opposite ends adapted for gripping said magnetic assembly, the fixing device comprising threaded portions, pair, and spacing means adapted for attaching adjacent to the fixing device and to be interposed between said magnetic assembly and the opposite faces of said element.

The present invention also relates to a loudspeaker for using said vibration 75 translator, the loudspeaker being in turn characterized by an element having the capacity to maintain and propagate, through bending waves, vibrational input energy, at least an active area that extends transversely on the thickness, to have vibrating components of resonant type, distributed over the respective area, and to have preferential locations or locations, predetermined, within that zone, for arrangement in one of 80 respective sites or locations , of a transducer mounted integrally and exclusively, on said radiant element, to determine the vibration of said radiant element, so that it enters the resonance, thus forming an acoustic transmitter that generates an acoustic radiation when it resonates.

The vibration transducer, according to the invention, has the advantage of obtaining resonant-type vibrational components distributed within an active area, respectively the diffuser using such a translator presents, in its turn, the following advantages:

- has a simple, light weight construction, being easy to make;

- it allows to obtain a uniformly distributed sound from the point of view of frequencies and of a higher stereophonic effect, compared to that of the conventional loudspeakers; 90

- has special properties for shielding radio frequencies and reducing stationary wave effects.

The following is an exemplary embodiment of the invention, in connection with FIG.

- Figure 1, constructive diagram of a distributed type diffuser, according to the description of the invention 95 from the publication of PCT patent application WO97 / 09842;

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- Fig. 2a, view through a partial cross section, following the section line A-A of fig. 1;

- Fig. 2b, view through a cross-section, on an enlarged scale, of a radiant element with a distributed operation, of the type of the one in fig. 2a, presented in two embodiments;

- fig.3, the constructive diagram of a translator according to the invention, in a first embodiment;

- Fig. 4 constructive diagram of a translator according to the invention, in a second embodiment.

Figure 1 shows a panel 81 speaker, of the type described in PCT patent application publication WO97 / 09842, whose applicant is the same as the PCT patent application that was the basis for opening the national phase of the present application. patent, the diffuser 81 having a rectangular frame 1 formed by means of elastic suspension means 3 arranged around its internal peripheral contour, supporting a radiant element 2, acoustically, in the form of a panel, of distributed type (with distributed operation). A translator 9, for example of the type that is widely presented in PCT patent application publications WO97 / 09859, WO97 / 09861, WO97 / 09859 having the same date and the same applicant as the PCT patent application, is mounted entirely and exclusively on, or within the radiant element 2 in the form of a panel, in a predetermined location, defined by the x and y coordinates, and whose location is calculated according to those presented in the publication of PCT patent application W097 / 09842, mentioned above, for the purpose to produce, in the panel, a bending wave that causes its resonance entry, in order to generate an acoustic output emission.

The transducer 9 is controlled by a signal amplifier 10, for example, an audio frequency amplifier connected to the transducer by means of conductors 28. The signal amplifier load 10 and the power requirement may be the normal ones, similar to those of conventional conical speakers, and the sensitivity is of the order of 86 + 88 dB / watts when used in a furnished room. The load impedance of the signal amplifier 10 is largely resistive, being 6 ohms, which dissipates a power of 20 + 80 watts. When the core and / or film layers of the panel are metallic, they can be made astrally so that they act as a heat radiator of the transducer, to evacuate the heat from the coil of the translator-motor assembly of the transducer and thus improve the energy balance.

Figure 2a and 2b show partial cross-sections, typical for the speaker 81 of Figure 1. in FIG. 2a shows how the frame 1, the elastic suspension means 3 and the radiant element 1 in the form of a panel, are connected together, using some adhesive jointing means 20. As suitable materials for the realization of the frame 1 we mention the light frame type structures. painting made of extruded metal, aluminum or plastic alloy. For elastic suspension means 3 it is advisable to use elastic materials such as, for example, rubber or plastic, both of foam type. As suitable materials for adhesive bonding means 20, we mention epoxy, acrylic, cyanoacrylate adhesives, etc.

in FIG. 2b is shown, on a larger scale, the radiant element 2 in the form of a lightweight, rigid panel, comprising a core 22 made of a rigid foam 97, made of plastic, such as cross-linked polyvinyl chloride, or a matrix cell 98 having a honeycomb structure made of metal foil, plastic or other similar material, and whose cells are transversely arranged, in relation to the plane of the panel, being closed by two opposite film layers 21, made, for example , of paper, cardboard, plastic or of sheets or

R0119055 Β1 metal sheets. When the film layers 21 are made of plastic, for growth of its module 145 (Young), they may be fiber reinforced, in a manner known per se, the fibers being, for example, carbon, glass, Kevlar ® or the like.

Proposed materials for achieving the coating and curing film states include carbon, glass, Kevlar®, Nomex® meaning aramid fibers, etc., of different structures and textures, such as paper, laminated pressed paper, melamine and various coats. 150 casts of high modulus (Young) synthetic plastics, such as Mylar®, Kaptan®, polycarbonate, phenol, polyester or associated plastics, and fiber-reinforced plastics, etc. and sheets and sheets of metal. The studies and researches carried out on the Vectra class of polymeric thermoplastic materials with liquid crystals have shown that they can be used with good results for the injection molding of the coating film layers or of the 155 ultrathin coatings of relatively small size, for example with diameters up to about 30 cm. This material itself forms a structure with crystals oriented in the direction of injection, offering a preferential orientation for better propagation of acute energy, from the point of action to the edges of the panel.

In addition, such a technique for forming thermoplastics of the aforementioned 160 or other type allows the assembly of forming machines to transport positioning and centering pieces, such as, for example, grooves or rings for precise placement. parts of the transducer, such as the motor coil assembly and the magnetic suspension. Moreover, for some types of materials, less resistant, used in the preparation of the core, it is considered that it would be advantageous to increase locally, up to 150% of the 165 diameter of the transducer, the thickness of the covering film state, for example on a portion or on a circular surface, in order to increase the resistance of the respective portion or surfaces and to advantageously couple the vibrational energy in the panel. In this way, by using softer sponge materials, the high frequency response is improved.

The materials used to make the core used as a core are 170 honeycomb shaped or have a corrugated appearance, being made from sheets or sheets made from aluminum alloys or Kevlar ®, Nomex ®, ordinary or pressed paper, and from different types of paper. synthetic plastic film layers, such as expanded or spongy plastics, or even paste materials, including metal aerogels if they are of sufficiently low density. Some of the materials suitable for making the layer 175 used as a core have practically the property of automatically forming their coating film states at the time of manufacture and / or may have an inherent rigidity sufficient to be used between the coating film layers. without requiring rolling. Another material that can be used in making the core used as a core and having the trade name 'Rohacell', is known for its high performance, being of the type without 180 film coating, the material can be used as a radiant panel. Basically, the aim is to obtain a material of low weight and overall rigidity corresponding to a particular application, assuming including optimization especially of the layers used as core, of the coating film layers and of the portions between them. 185

Some of the preferred embodiments of such a panel use metal sheets or sheets of metal alloys, or as an alternative, use a carbon fiber reinforcement. Both of the above solutions, as well as other metal or aerogel honeycomb structures (Kevlar and carbon alloy), used as a core, have special radio frequency shielding properties, which is of particular importance in 190 different EMC applications. Conical type speakers or conventional panels do not have such inherent EMC shielding properties.

In addition, it should be borne in mind that, in the preferred embodiments of the invention, piezoelectric and electrodynamic transducers have electromagnetic radiation or magnetic fields of dispersion of negligible intensities. Conventional loudspeakers have large magnetic fields, which can reach up to one meter in distance, unless specific countermeasures are taken.

In the case of applications where good shielding is required, electrical connections can be made to the electrically conductive parts of a corresponding type DML panel or to an electrically conductive foam, or an interface similar to those used for mounting the edges can be used. .

The elastic suspension means 3 provide the damping of the edges of the panel 2 to prevent excessive displacement of the edges of the respective panel. In addition or as a displacement variant, it can also be used as a damping, for example, applying patches fixed to the panel in certain preselected positions to attenuate excessive movements in order to ensure uniform distribution of the resonance throughout the panel. . Such patches can be made of material made of bitumen, usually used in the enclosures of conventional speakers, or they can be made of a polymeric, laminated, elastic or rigid material. Some materials, especially paper and cardboard, as well as some materials used as a core, may exhibit self-attenuation properties. When desired, when making the panel, the damping can be increased by the use of adhesives whose elastic hardening, instead of the use of some rigid hardening.

A selective and efficient cushioning implies a specific application on the panel and also on the laminated material which is an integral, permanent part thereof. The edges and corners may prove particularly important for low frequency vibration modes of the panels, which are dominant and of lower dispersion. Fixing the edges, for a cushioning element, can usefully lead to obtaining a panel whose material, in laminated form, is completely trapped on the edges, even though its corners will remain relatively free, for example to allow for possible extension of operation at relatively low frequencies. The fixing can be done with the help of adhesive or even self-adhesive materials. Other useful forms of depreciation, especially when pursuing certain special effects and / or medium and high frequencies, may be in the form of one or more appropriate weights, fixed by the laminated material in certain predetermined positions, practically located medially within the respective area.

An acoustic panel of the type described above is bidirectional. The energy of the sound coming from the rear speaker is not very correlated with that of the sound coming from the front speaker. As a result, you get the benefit of a global summation of acoustic power in the room, a uniformly distributed sound energy from the point of view of frequencies, reduced stationary wave effects and with the advantage of better reproduction, sound, space and ambient playback. naturally registered.

If the radiation emitted by an acoustic panel is largely non-directional, it must be taken into account, however, that the percentage correlation of the acoustic information increases outside the axis. For a better focus on artificially created stereo images, the layout of the speakers, as well as the images, at the height of a person standing has the advantage of an easy off-axis position for listeners who are usually seated, which leads to optimization of the stereo effect. Similarly, the left / right triangular geometry that includes the listener provides an additional angular component. In this way, a good stereo effect can be obtained.

For a group of listeners there is an advantage, compared to playing using a conventional speaker. By the nature of dispersion that intrinsically characterizes the sound emission made by the acoustic panel, a volume of sound is produced which

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245 does not satisfy the law of dependence inversely proportional to the square of the distance, for an equivalent point source. Due to the fact that the intensity reduction with the distance is much smaller than that determined by applying the dependence law inversely proportional to the distance square, it will result that for the non-centrally located listeners, who occupy disadvantaged places, the field intensity for the panel type speaker will produce a higher stereo effect. , compared to that of conventional speakers. This is due to the fact that the non-centrally located listener is no longer subject to double shortcomings due to the proximity of the speaker in the immediate vicinity: firstly the excessive increase of the volume of the nearby speaker, and secondly the corresponding reduction of the volume for the farther speaker.

There is also the advantage of a flat panel, low weight, nice looking, good looking sound quality speaker, requiring only a translator, without producing sound translations for a whole range of sounds from each diaphragm of the panel.

Fig. 3 shows an embodiment of the vibration transducer 9 for producing the waves in a radiant element 2 in the form of a panel, operating in a distributed manner, for example of the type shown in Figs. 1 and 2 containing a core 22 disposed between two film layers 21, opposite, to cause resonance in the panel.

The transducer contains a coil 13 rigidly fixed by adhesive means, on the outside of the body 18 of said coil 13 which is rigidly fixed to the surface of the film layers 21 of the radiant element 2 in the form of a panel, for example using some epoxy adhesive jointing means 16 . A magnet 15 is located, enclosed, between a pair of poles 14, one of which is disk type, being disposed with its peripheral contour around the inner part of the body 18 of the coil 13, and the other has a peripheral edge 90 which surround coil 13.

The magnetic assembly including magnet 15 and pole 14 is mounted on a panel 2 by means of fastening means 93, for example from metal or hard plastics, which pass through an opening 29 which continues into the radiant element 2 in the form of a panel. . The fastening means 93 contain a complementary pair of threaded elements 91, 92 each being provided with ends 95, one of which rests on the outer face of the vibration transducer 9, and the other on one of the faces of the radiant element 2 in the form of a panel, opposite the one on which the vibration transducer 9. is mounted. A spacer 127 is mounted between the vibration transducer 9 and the radiant element 2 in the form of a panel, for the purpose of separating them.

Operation of the vibration transducer 9 in fig. 3 consists of the local, elastic bending of the panel, between the fastening means 93 and the body 18 of said coil 13, when an acoustic signal is applied to the vibration transducer 9 which, producing bending waves in the panel, causes its resonance.

The configuration of the vibration transducer 9 in fig. 4 is similar to that in Fig. 3, except that in this variant the vibration transducer 9 contains push-puH complementary exciters of the type shown in Fig. 3 and which are arranged on the opposite sides of the panel. are provided to pass through the opening 29 to enter the radiant element 2 in the form of a panel, in order to unite on the panel some vibration transducers 9, pair. The fastening means 93 are composed of complementary parts, respectively of type threading elements 91 and 92, pair, provided each with ends 95, which are tightly gripped by the axial ends of said vibration transducers 9, of type pair, mentioned, realizing - thus the coupling of the complementary exciters of the push-puH type is combined. The complementary parts of the fastening means 93 are intertwined on threaded portions 94 and 96, also complementary. The fastening means 93 can be made of any suitable material, for example, plastic or metal.

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In this embodiment, the vibration transducer 9 is rigidly fixed to the panel-shaped radiant element 2 by means of rigid contact pieces 19, for example, from rigid, positioned plastics, adjacent to the opening 29, between the radiant element 2 in panel shape and poles 14, so that the vibration transducer 9 produces bending waves in the panel, by local, elastic bending of the panel, between the contact parts 19 and the body 18 of the coil 13.

Claims (7)

1. Vibration transducer characterized in that, for the purpose of activating a radiant element (2), single face, having the capacity to maintain and propagate, through the bending waves, vibrational energy of input, in at least one active area that extends transversely on thickness, in order to obtain vibrating components of resonant type distributed on the respective area, within which there are sites or preferential locations, predetermined, of that area, in which the arrangement of the respective vibration transducer (9) is mounted, mounted on the element said radiator (2), to determine the vibration of said radiant element (2), so that it resonates, forming an acoustic emitter which generates acoustic radiation when it resonates, the vibration transducer (9) comprises a coil assembly -motor (13.18) having a coil (13) rigidly fixed by a tubular element (18), the motor-coil assembly (13.18) being adapted for fixing on said face of said radiant element (2), and a magnetic assembly (15) having polar parts (14) opposite, in disc form, the end of one of the polar parts being adapted for the position in position adjacent to the motor-coil assembly (13,18), and the end of the other polar piece containing a peripheral edge (90) which is adapted to dispose, in an adjacent position, around the coil-motor assembly (13,18), the vibration transducer (9) in which the assembly magnetic (15) is adapted for fixing, with its central part, the said radiant element (2), in order to be vibrated. 2. The vibration transducer according to claim 1, characterized in that said vibration transducer (9) comprises fastening means (93) for fastening the magnetic assembly (15) of said radiant element (2). The vibration transducer according to claim 2, characterized in that the fixing means (93) comprises a fastening member (91.92) adapted for penetrating a cavity (29) within said radiant element (2). 4. The vibration transducer according to claim 3, characterized in that the fixing member (91.92) comprises a spacer (127) for separating the ends of the polar parts (14) from said radiant element (2). 5. The vibration transducer according to any one of the preceding claims, characterized in that, in an embodiment in which the radiant element (2) is of double-faced type, the vibration transducer (9) comprises two coil-motor assemblies (13, 18) and two complementary magnetic assemblies (15), which are adapted to be mounted on the two opposite sides of said radiant element (2), as well as fastening means (93) which unite the centers of the magnetic assemblies ( 15), for symmetrical operation. 6. The vibration transducer according to claim 5, characterized in that the fastening member (91.92) is provided with opposite end ends (95), being adapted to come into contact with the respective magnetic assemblies (15), the fastening member ( 91.92) comprising some threaded areas (94.96), of pair type, which are joined to each other, there being some distal means (19) which have been adapted to be disposed adjacent to the fixing member (91, 92) and to be interspersed between the respective magnetic assemblies (15) and each of the two opposite faces of said radiant element (2). ί R0119055 Β1 340 7. Speaker for using the vibration transducer of claim 1, characterized in that said speaker (81) comprises a radiant element (2) having the capacity to maintain and propagate, through the bending waves, input vibrational energy, at least an active area that extends transversely on the thickness, to have vibrating components of resonant type distributed over the respective area, and to have preferential locations, or locations, predetermined, within that zone, for arrangement, in one of those sites or locations, of a vibration transducer (9) integrally and exclusively mounted on said radiant element (2), to determine the vibration of said radiant element (2), so that it enters the resonance, thus forming an acoustic transmitter which generates a acoustic radiation when it resonates.