RO119040B1 - Suspended ceiling tile - Google Patents

Abstract

The invention relates to a suspended ceiling plate, incorporating a diffuser (81), said suspended ceiling plate (36) having the form of an acoustic radiating element (2), distributed type, on which is mounted, integrally and exclusively, a transducer (9), in order to produce the vibration of the radiant element (2) and cause it to enter resonance. à

Description

The invention relates to a suspended ceiling plate, in which a loudspeaker of the type containing radiant acoustic elements, in the form of a panel, is incorporated.

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

- a radiant element in various modes, 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, independent of direction, a coefficient of resistance to bending (B) equal to the mass of the panel at power 3, per unit area (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.

There is a wide use of loudspeaker speakers, made as standard mode, which can be replaced with commercially available ceiling plates, generally 600 x 600 mm in size, and aimed at uniform distribution over a large area. articulated speech and music. For such an application, at present, some excitatory means with movable coil are realized, as well as panel-derived products.

The existing technology uses conical mobile coil speakers that are fixed in frame type supports and acoustic panels. Although commonly used, for their moderate price and for the ease with which they can be purchased, they still suffer from very hot points (excessive sound intensity) and directional effects and, consequently, due to poorer intelligibility outside. longitudinal axis of the speaker, requiring more acoustic units to obtain a uniform coverage over a larger area.

Another known solution uses a conical diffuser, in which the conical element is a polystyrene structure having a flat front surface, which can be painted. within it, a combination of excitatory means with movable coil, mounted on their diaphragm structured to perform acoustic contraction with increased frequency, can provide a wider emission configuration, compared to a conventional conical speaker. These polystyrene foam acoustic units require a chassis and acoustic screens to be mounted in position.

US Patent No. 4506117, holder MULTIPHONIE, is presented a suspended ceiling plate provided with an electroacoustic transducer having a metal base plate, through which the panel is made in solidarity.

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, the applicant of which is the same as the one of the application. PCT patent which was the basis for opening the national phase of this patent application. Such elements have the capacity to maintain and propagate, by means of flexural waves, vibration energy of entry, in the operational area or zones, 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 stiffness 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, for the disposal of a translator in the respective zone or areas, in particular in that part or operationally active or movable parts thereof, effective in respect of

EN 119040 Β1 the activity of the acoustic vibration and as regards the signals, usually electrical, corresponding to the acoustic content of such a vibrational activity. 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 filtering or for achieving a harmonic. acoustics in a space or in a room; and in the acoustic devices active with the transducer, 55 such as, for example, 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 they are, for example , microphones, when exposed to an audible signal to be converted to another signal.

The invention relates to a suspended ceiling plate, made in the form of an active acoustic speaker type 60 device.

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. 65

The invention relates to a suspended ceiling plate, incorporating a diffuser, characterized by an element having the capacity to maintain and propagate, by means of flexural waves, vibratory energy of entry, in at least one active area that extends transversely on thickness, to have vibrating components of resonant type, distributed on the respective area, and to have preferential locations or locations, predetermined, within that 70 zone, for arranging in one of those locations or locations, a fully and exclusively mounted translator, on said radiant element, to determine the vibration of said radiant element, so that it resonates, thus forming an acoustic emitter which generates an acoustic radiation when it resonates. The suspended ceiling plate is characterized by a radiating element, containing a cellular core, for example 75 feet of spongiform plastic material, arranged between high-modulus (Young) film layers. Some elastic suspension means may be disposed at the periphery of the radiant element to support the radiant element within the suspended ceiling. The transducer can be an inertial vibration transducer.

The following is an example of an embodiment of the invention, in connection with 80 FIGS. 1-3, which represents:

- Fig. 1, constructive diagram of a distributed type diffuser, according to the description of the invention in the publication of PCT patent application WO97 / 09842;

- Fig. 2a, view through a partial cross section, following the section line A-A of fig. 1; 85

- 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. 3a, perspective view of a room incorporating a suspended ceiling;

- Fig. 3b, a cross-sectional view of a 90-degree distributed type diffuser, according to the invention, in the form of a suspended ceiling plate.

Figure 1 shows a panel-shaped speaker 81, of the type described in PCT patent application publication WO97 / 09842, the applicant of which is the same as the PCT patent application that was the basis for opening the national phase of the present patent applications, the diffuser 81 having a rectangular frame 1, of which some means of elastic support 3 are fixed 3, arranged around its internal peripheral contour, which support a radiant element 2, acoustic, in the form of panel, of distributed type (operating in mod

RO 119040 Β1 distributed). 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 / watt 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 the film layers of the panel are metallic, they can be made to act as a heat radiator of the transducer, to evacuate the heat from the coil of the coil-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 realizing the frame 1, we mention the light frame type structures. painting, made of extruded metal, aluminum or plastic alloy. For the 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.

Figure 2b shows, 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, for example, cross-linked polyvinyl chloride , or a cell matrix 98 having a honeycomb structure, made of metal foil, plastic or other similar material, and whose cells are arranged transversely, in relation to the plane of the panel, being closed by two film layers 21, opposite, made, for example, of paper, cardboard, plastic or sheet or sheet metal. When the film layers 21 are plastic, for growth of its (Young's) module, 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 the coating and curing film states include carbon, glass, Kevlar®, Nomex® meaning aramid fibers, etc., of various structures and textures, such as paper, laminated pressed paper, melamine and various mass films. High modulus (Young) synthetic plastics, such as Mylar®, Kaptan®, polycarbonate, phenol, polyester or associated plastics, and fiber-reinforced plastics, etc., sheets and sheets. 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 films or of the ultra-thin 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.

IIW I JVTU UI, in addition, such a technique for forming thermoplastics of the aforementioned or other type allows the assembly of forming machines to transport positioning and centering pieces, such as, for example, grooves or rings. for the precise placement of the transducer parts, 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 diameter of the translator, 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. 155

The materials used to make the core used as a core are honeycomb shaped or have a corrugated appearance, being made from sheets or sheets made from aluminum alloys or Kevlar®, Nomex®, plain or pressed paper, and from different types of layers. films made of synthetic plastics, 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 core 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 require rolling. Another material that can be used for making the core used as a core and having the commercial name 'Rohacell' is known for its high performance, being of the type without a covering film layer, the material can be used as a radiant panel. Basically, the aim is to obtain a material of low weight and overall rigidity, suitable for a particular application, assuming including the optimization especially of the layers used as core, of the covering film layers and of the portions between 170 these two.

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 175 radio frequency shielding properties, which is an element of particular importance in 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 be up to one meter apart, 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 DML panel of the corresponding type 185 or to an electrically conductive foam, or an interface similar to those used in mounting can be used. edges.

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, to apply panels 190 fixed to the panel in certain preselected positions to attenuate excessive movements in order to ensure uniform distribution of the resonance on the panel. the entire contents of the panel. Such patches may be made of bitumen-based material, typically used in conventional speaker enclosures, or may be made of a polymeric, laminated material,

RO 119040 Β1 elastic or rigid. 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 using adhesives whose hardening is elastic, instead of using 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. consequently, the advantage of a global summation of the acoustic power in the room is obtained, a uniformly distributed sound energy in terms of frequencies, reduced stationary wave effects and with the advantage of better reproduction, in the reproduction of sound, space and environment. 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 placement for listeners who are usually seated, what leads to optimization of the stereo effect. In the same way, the left / right triangular geometry, which 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 that does not satisfy the dependence law 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 the one determined by applying the dependence law inversely proportional to the square of the distance, it will result that for the non-centrally located listeners, who occupy disadvantaged places, the intensity of the field for the panel type speaker will produce a stereophonic effect. superior to that of conventional speakers. This is because the non-centrally located listener is no longer subject to double shortcomings due to the proximity to the speaker in the immediate vicinity: first, the excessive increase in the volume of the speaker located nearby, and secondly, the corresponding reduction in volume for the speaker further away. .

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 a plate 36 of suspended ceiling of the type that allows the adaptation in a frame 99, suspended, in the form of a grid, which forms the suspended ceiling and which is formed as a speaker 81, as shown in fig. . 1 and 2, which contains one

RO 119040 Β1 radiant element 2 multimodal resonant, light, rigid having a core 22 disposed between two layers 245 21 relative to both sides. The radiant element 2 has, at the periphery, an elastic suspension 3 of foam rubber material, which is supported on the frame 99. The suspension 3 can be attached to another radiant element 2 or to a frame 99 by adhesive means, but the connection can only be through gravity. The radiant element 2 supports a transducer9, for example of the type shown in Figs. 1 and 2, the production of flexural waves in the panel causing acoustic resonance 250 at the output. The translator 9 may be positioned on the panel as described in the aforementioned PCT patent application publication WO97 / 09842.

In a preferred example, in order to obtain a good quality acoustic panel, it is made with the foam polystyrene core usually expanded with a density of 100g / m ³ , a thickness of 8 mm, covered with layers of aluminum alloy of 0.1 mm. A soft foam mattress or a 3 mm thick felt strip is fixed around the edges to ensure a good partial fit when placed in the ceiling frame and also helps to dampen any possible vibration in the frame sections. 99 of the ceiling.

A preferred way to obtain excitations is to use an inertial transducer 260 with movable coil, having an acoustic coil of 25 mm or 38 mm, impedance of 6 ohms, power of 40 watts, with the coil directly attached to the surface of the panel. A compact magnetic funnel type self-sealing closed system can be directly attached to the panel through an elastic decoupling ring, chosen for its vibromechanical properties and dimensional stability.

Depending on the application, a low-cost ceiling plate can be made from a paper-coated cardboard material with a spongiform plastic core, which may have a foil-like layer of light alloy for protection against fire, excited by low cost piezoelectric vibration exciters. Low levels of maximum sound are obtained, being more than sufficient for personal announcements, voice-over and music background making. Coverage of a large area is maintained. 270

When using metallic or carbon conductive cores or layers, the diffuser can be grounded to maintain the EMC shielding of an accomplished structure.

The suspension plate type speaker, according to the invention, does not require a frame, chassis or acoustic panel, the entire panel-shaped speaker being unitary and can be placed in 275 positions, even as a purely decorative ceiling plate. The acoustic panel is relatively lightweight, reducing the load on the ceiling and related installations. It can be made to be fire resistant. It can be decorated, painted or upholstered, to become invisible in the ceiling installation without significant acoustic damage.

Minor defects do not affect the yield, compared to the diffuse diaphragms - 280 conical type relays which are very fragile. It is also of great importance the advantage regarding the distribution of the sound given by the acoustic speaker type panel. This combination of high intelligibility and wide-angle media is reflected, in a large installation, in that a higher acoustic efficiency can be achieved, with a reduction of approximately half the number of speakers normally required, and 285 with a great saving of installation cost.

Claims (5)

claims 1. Suspended ceiling plate, in which a loudspeaker (81) is incorporated, characterized 290 in that said suspended ceiling plate (36) comprises a radiant element (2) having the capacity to maintain and propagate, by means of bending waves, vibrational energy of EN 119040 Β1 entrance, in at least one 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 the arrangement, in one of said locations or locations, a 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 that generates acoustic radiation when it resonates. Suspended ceiling plate according to claim 1, characterized in that the radiating element (2) has a cellular core (22), interspersed between layers (21) of high modularization. Suspended ceiling plate according to claim 1 or 2, characterized in that said plate (36) comprises elastic suspension means (3) disposed at the periphery of the radiant element (2), to support the radiant element (2), in -a chassis (99), from the suspended ceiling. Suspended ceiling plate according to claim 2 or 3 depending on 2, characterized in that the cell core (22) is made of a foam plastic material (97). 5. Suspended ceiling plate according to any one of the preceding claims, characterized in that said transducer (9) is an inertial vibration transducer. The chairman of the examination committee: Eng. Popescu Livia