A hybrid sound emission device for vibrating heavy rigid plates with sound frequencies.

Abstract

A hybrid sound radiating device according to the invention is used to vibrate a heavy rigid plate at audio frequencies. The device comprises two voice coils arranged concentrically, the outer voice coil being coupled to a fluid reservoir containing a medium including three fluids with a substantially constant viscosity depending on the frequency. A third coil is arranged around the side wall of the fluid reservoir, and two electrodes with opposite polarity are provided in the fluid reservoir to provide a substantially constant electric field in the fluid reservoir. The device further comprises a vibrating element in the form of a heavy rigid plate rigidly connected to the fluid reservoir, and a control circuit connected to the first, second and third coils and to the electrodes.

Description

Technical Field

[0001] The present invention relates to an acoustic radiation device in which an electromechanical transducer and a vibration transducer including a liquid are integrated to vibrate a heavy rigid plate at an audio frequency.

Background Art

[0002] According to the current technical situation, loudspeakers of various designs are known. Widely used speakers and other speaker devices are essentially physical systems that convert an input voltage signal into vibrations at an audio frequency. In loudspeakers, diaphragms and vibration transducers of different designs are known according to usage requirements.

[0003] Patent Document 1 discloses a modular speaker in which a plurality of integrated mechanisms vibrate a panel to generate an acoustic output. These mechanisms can be, for example, a movable coil unit, a movable magnetic unit, or a piezoelectric unit. The individual mechanisms are connected to each other via switching elements, and these switching elements ensure the transmission of energy to the panel. By combining different mechanisms, the output of the modular speaker can be adjusted and optimized.

[0004] Patent Document 2 discloses a loudspeaker having a switching unit including a rheological medium. The rheological medium may be a magnetorheological fluid or an electrorheological fluid. By controlling the viscosity of the rheological medium, the vibration transducer can be firmly or elastically connected to the acoustic vibration element, and as a result, when a flexural wave is excited by the device, an acoustic output can be brought about on the vibration element.

[0005] The drawback of the above solutions is that the vibration transducer is only suitable for vibrating a lightweight vibration element that can be elastically deformed by vibration, and is not suitable for vibrating a heavy rigid sheet such as a glass sheet or a stone sheet at an appropriate audio frequency.

[0006] Vibrations of heavy, large, rigid vibration elements such as glass or stone plates at low frequencies can be realized by one or more large vibration transducers capable of generating sufficiently large forces. Vibrations of such heavy, rigid plates at higher frequencies, typically above 1000 Hz, cannot be achieved with conventional electroacoustic transducers without significant degradation of sound quality. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] European Patent Application No. 1250827 [Patent Document 2] U.S. Patent Application No. 2005226445 [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to overcome the above-mentioned problems by providing a sound radiating device capable of vibrating large, heavy rigid plates in low-range and high-range audio frequency spectra having substantially linear transmission characteristics. [Means for solving the problem]

[0009] These objectives are achieved by a hybrid sound emission device as defined in the attached claims.

[0010] The present invention will now be described in more detail with reference to the drawings. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view of the structure of the hybrid sound vibration system according to the present invention. [Figure 2]This figure schematically shows the device design of the electronic control unit for the hybrid sound and vibration system according to the present invention. [Figure 3] This figure shows the structural design of the hybrid sound vibration device according to the present invention, with partial longitudinal cross-sectional views and partial perspective views. [Figure 4] This is a perspective view of the structure of the hybrid sound vibration device according to the present invention. [Figure 5] This figure shows the hybrid sound vibration device according to the present invention in an assembled state, ready for immediate installation. [Modes for carrying out the invention]

[0012] As shown in Figures 1 and 3 to 5, the hybrid sound vibration device 100 of the present invention includes a vibrating element 160 formed as a large, heavy, rigid plate. The material of the vibrating element 160 is preferably sandstone, stone, glass, wood, etc. The vibrating element 160 is particularly preferably an indoor wall covering element. The outer surface of the vibrating element 160 according to the present invention, i.e., the surface facing the acoustic space, may be flat, but it may also be a surface having a spatial (3D) pattern suitable for generating acoustic waves.

[0013] The actuation unit of the hybrid acoustic vibration device 100 can be located on the front side of the vibrating element 160, i.e., the back side generally hidden from the user. The device 100 has a fixed-position support member 120 that fixes the device 100 to the ground or other rigid support structure. The support member 120 may include one or more unloading support members that substantially hold the vibrating element 160 and thereby release the other components of the hybrid acoustic vibration device 100.

[0014] The primary resonator 200 is directly connected to the fixed support member 120. The primary resonator 200 is designed as a movable coil unit that can move freely in a given axial direction within a magnetic field in response to an applied voltage, as is known in conventional electrodynamic loudspeakers, thereby generating acoustic vibrations.

[0015] The primary resonator 200 includes at least one permanent magnet 210 in a fixed position, and the magnetic axis of the permanent magnet 210 is orthogonal to the plane of the vibration element 160. Hereinafter, the direction of the magnetic axis of the permanent magnet 210 is referred to as the primary axis direction 110. The permanent magnet 210 attached to the support member 120 provides a very strong and uniform magnetic field for the primary resonator 200. The material of the permanent magnet 210 is preferably neodymium or a neodymium-containing material or alloy.

[0016] Preferably, a first coil 220 is fixedly disposed around the permanent magnet 210. The central axis of the first coil 220 is parallel to the primary axis direction 110. The homogeneity and the strength of the magnetic field of the first coil 220 disposed on the permanent magnet 210 are enhanced by the permanent magnet 210, and thus, by using both the permanent magnet 210 and the first coil 220, the linearity of the transmission characteristics of the primary resonator 200 can be improved.

[0017] A movable coil unit is disposed around the first coil 220, and the movable coil unit includes a support member 230 and a second coil 240 disposed on the support member 230. The support member 230 is substantially cylindrical and annular, and the second coil 240 is preferably wound around the outer surface of its cylindrical shell. A gap is formed between the inner surface of the movable coil unit and the first coil 220, and thus, the support member 230 having the second coil 240 can be moved along the primary axis direction 110 with respect to the first coil 220.

[0018] Preferably, the primary resonator 200 can have a first magnetic shield 250 on the side facing the intermediate member 140 of the support member 120 and a second magnetic shield 260 on the side of the intermediate member 140 facing the support member 120.

[0019] The shielding elements 250, 260 magnetically isolate the permanent magnetic field within the primary resonator 200 from other parts of the hybrid acoustic vibration device 100. The magnetic shielding elements 250, 260 are preferably made of a material having a high magnetic permeability.

[0020] To operate the primary resonator 200, the hybrid sound radiation device 100 includes a control circuit 270 as shown in FIG. 2. The control circuit 270 provides an applied voltage corresponding to the first coil 220 and provides a voltage signal of an audio frequency to the second coil 240. Thus, the primary resonator 200 (or more precisely its movable coil) generates mechanical vibrations within a frequency range of 20 Hz to 20,000 Hz. The control circuit 270 includes conventional electronic circuit units well known to those skilled in the art for the above-described purposes.

[0021] The end of the support member 230 that is away from the support member 120 is fixed to the first side of the movable intermediate member 140. The support member 120 further has at least one, preferably four guide support members 130. The guide support members 130 guide the reciprocating intermediate member 140 along the primary axial direction 110 while holding it on one hand and following the vibration of the movable coil on the other hand. Thus, the vibration of the second coil 240 is transmitted to the intermediate element 140 substantially without distortion.

[0022] The intermediate member 140 is preferably formed from a composite material, thereby minimizing the weight of the intermediate member 140 and unwanted inherent vibrations while maintaining mechanical efficiency. In a preferred embodiment of the device 100, the guide support member 130 is connected to the intermediate member 140 by a damping member 134 made of rubber. The purpose of the directional damping is to absorb and damp any vibrations and resonances within the structural elements other than the vibration element 160 so that such vibrations do not transfer to the rear support element 120 as much as possible (or preferably at all). In many cases, the rear support element is directly connected to the stationary structure of the building.

[0023] The guide support member 130 neutralizes the shear force acting on the unit 240 formed by the coil 240 and the permanent magnet 210. To minimize any negative effects on the sound, the guide support element 130 should preferably be connected to the intermediate element 140 via the damping member.

[0024] A secondary resonator 300 is connected to the second side of the intermediate element 140, which is located opposite the first side. The function of the secondary resonator 300 is to transmit the mechanical vibrations generated by the primary resonator 200 to the heavier vibrating element 160.

[0025] The secondary resonator 300 includes a fluid reservoir 320 having side walls 320 of variable length along the primary axis direction 110. The side walls 320 of variable length are preferably composed of wall portions that are sealed to each other, but optionally the side walls can be walls of flexible elastic sheets by bending the length of the fluid reservoir along the primary axis direction 110.

[0026] A third coil 330 is positioned around the fluid reservoir, and the central axis of the third coil 330 is parallel to the primary axis direction 110, generating a magnetic field within the fluid reservoir.

[0027] Preferably, a first electrode 340 is positioned in the fluid reservoir on the side connected to the intermediate member 140, and a second electrode 350 having the opposite polarity is positioned opposite the first electrode, preferably in the fluid reservoir, to generate a substantially constant electric field within the fluid reservoir.

[0028] The fluid reservoir is filled with a medium 310 consisting of a mixture of at least two non-Newtonian fluids and a magnetic fluid. One non-Newtonian fluid is a thixotropic composite elastomer such as polydimethylsiloxane (PDMS, C2H6OSi). The other non-Newtonian fluid is lithium hydroxystearate (C2H6OSi). 18 H 35 A mixture of LiO3 with silicone oil has rheopexic properties. The proportion of the rheopexic material in the mixture is about 20% by volume, meaning the mixture contains about 80% by volume of silicone oil. The ratio of the two non-Newtonian fluids in medium 310 is preferably about 30% by volume of thixotropic fluid and 70% by volume of rheopexic fluid.

[0029] The medium 310 also contains a magnetorheological fluid, and therefore the entire medium 310 is continuously located in an electric field by electrodes 340 and 350, causing the medium to vibrate at an audio frequency. The volume ratio of the magnetorheological fluid in the medium 310 is preferably close to 40%.

[0030] As the magnetorheological material, for example, a magnetite-based magnetic fluid containing dispersed magnetite or iron particles with coarser particles (diameter approximately 0.1 to 50 micrometers) is used. The resulting magnetorheological fluid behaves in an external magnetic field similarly to an electrorheological fluid in an external electric field. That is, the particles are organized into chains and rows parallel to the field lines by the magnetic field, resulting in a several-order-of-magnitude increase in fluid viscosity. After the magnetic field is removed, the chains also stop within a few milliseconds, and the fluid viscosity returns to its original value.

[0031] For optimal operation, the temperature of the medium 310 should preferably be between 1°C and 70°C. The capacity of the liquid container should preferably be about 50 cm³. 3 It is to that extent.

[0032] The magnetorheological fluid forming the medium 310 preferably contains iron oxide (FeO) particles having a particle size of several tens of nanometers to several micrometers. Under the influence of a time-varying magnetic field provided by the third coil 330, the medium 310 continuously changes its size in the primary axis direction 110 within the liquid container. This size change can occur up to approximately 5,000 times per second.

[0033] The medium 310 in the fluid reservoir is maintained within a substantially constant electric field by electrodes 340 and 350. This electrical bias is required to adjust the optimal viscosity of the medium 310, which contains two non-Newtonian fluids and a magnetorheological fluid. Based on the acoustic and physical properties of the acoustic waves generated by the hybrid sound emission device 100 using acoustic field measurements, the constant electric field strength can be fine-tuned using the control circuit 370, but this does not significantly affect the invariance of the electric field.

[0034] As a result of a suitable mixture of two non-Newtonian fluids and a magnetorheological fluid, a medium with substantially constant viscosity with respect to frequency is obtained, which behaves as a sufficiently large mass, high-inertia vibrating medium within a relatively wide frequency range (approximately 200 Hz to 5 kHz), thereby enabling the transmission of mechanical vibrations generated by the primary resonator 200 to the heavy vibrating element 160 with minimal strain.

[0035] To operate the secondary resonator 300, that is, to control the magnetic and electric fields of the medium 310, the device 100 according to the present invention comprises a control circuit 370 shown in Figure 2, the control circuit 370 provides suitable voltages to electrodes 340, 350 and provides an audio frequency signal to coil 330. The control circuit 370 operates the secondary resonator 300 such that the operation of the hybrid sound emitting device 100 as a whole is substantially linear.

[0036] The hybrid sound emission device 100 of the present invention may further include a special frequency transmission and pulse response compensation digital signal processing unit (DSP) 400 shown in Figure 2, and various acoustic sensors 402 for compensating for possible acoustic distortions observed in the irradiation space by control circuits 270 and 370.

[0037] On the side of the secondary resonator 300 opposite the intermediate element 140, a vibration transmission element 150 is preferably rigidly, preferably by adhesive, positioned on the corresponding wall of the liquid container on one side and on the heavier vibration element 160 on the other. As shown in Figure 5, not just one, but several, for example, four secondary resonators 300 can be connected to the vibration transmission element 150, thereby similarly transmitting a considerable amount of vibration energy to the heavier vibration element 160.

[0038] In a preferred embodiment of the hybrid sound emission device 100 of the present invention, the surface of the vibrating element 160 is approximately 1 m 2 ~20m 2The vibration transmission element 150 is fixed to the vibration element 160 by adhesive. The adhesive used forms a high-strength layer with minimal flexibility to transmit the vibrations of the vibration transmission element 150 to the vibration element 160 with as little strain and damping as possible. As shown in Figures 3 and 4, on the other side of the vibration transmission element 150, the vibration transmission element 150 can be connected to the outer end of a piston 132 that is movably positioned within the guide support member 130, so that the vibration transmission element 150 holds the vibrator 160 and thereby helps to release the fluid reservoir.

[0039] Although not shown in the drawings, the hybrid sound emission device 100 may further include additional conventional electronic units, such as power supplies, wiring, circuit breakers, etc., if necessary. The design and operation of these units are well known to those skilled in the art and will not be described in detail herein.

[0040] Under actual conditions, the hybrid sound emitting device 100 may be equipped with additional speakers, preferably tweeters and subwoofers, to meet higher user requirements. These auxiliary speakers are preferably concealed in the vicinity of the hybrid sound emitting device 100 of the present invention.

[0041] The advantage of the hybrid sound radiation device according to the present invention is that heavy, rigid panels such as wall covering panels can also be used as the speaker's vibration element, thus eliminating the need for conventional speakers that negatively affect the decorative appearance of a room, or allowing the unit to be installed completely hidden behind wall covering elements or furniture panels used as vibration elements.

[0042] A further advantage of the device according to the present invention over conventional wall-mounted loudspeakers is, for example, that minor damage or defects do not interfere with its operation. Due to its large vibrating element and special design, the hybrid sound radiating device has wide directivity, resulting in a spatially expansive sound distribution and good speech characteristics.

Claims

1. A hybrid sound radiating device (100) for vibrating a heavy rigid plate at sound frequencies, - A fixed support member (120), - A permanent magnet (210) with one end fixed to the support member (120), - A fixed first coil (220) is arranged around the permanent magnet (210), with its central axis defining the primary axis direction (110), - A second coil (240) is arranged around the first coil (220) and is movable along the primary axis direction (110), - The end of the second coil (240) that is away from the support member (120) is attached to the first side, and is guided along the guide support member (130) attached to the support member (120), and an intermediate member (140) that extends in the primary axis direction (110), - A fluid reservoir attached to the second side of the intermediate member (140) opposite to the first side, having a side wall of variable length along the primary axis direction (110), The fluid reservoir contains a medium (310) comprising at least one thixotropic fluid and a predetermined mixture of a rheopexy fluid and a magnetorheological fluid, wherein the medium (310) comprising the three fluids has a viscosity substantially constant with respect to frequency. A third coil (330) is arranged around the side wall (320) of the fluid reservoir, and the central axis of the third coil (330) is parallel to the primary axis direction (110). A fluid reservoir comprising a first electrode (340) provided on the side connected to the intermediate member (140) within the fluid reservoir, a second electrode (350) having the opposite polarity provided in the fluid reservoir facing the first electrode (340), and the electrodes (340, 350) providing a substantially constant electric field within the fluid reservoir, - A heavy, rigid, flat plate-shaped vibrating element (160) is rigidly connected to the side of the fluid reservoir opposite to the intermediate member (140), - A device comprising the first coil (220), the second coil (240), and the third coil (330), and control circuits (270, 370) connected to the electrodes (340, 350).

2. The device according to claim 1, wherein the second coil (240) has a cylindrical annular support member (230).

3. The device according to claim 1, wherein the side of the support member (120) facing the intermediate member (140), and the side of the intermediate member (140) facing the support member (120), have magnetic shielding elements (250, 260).

4. The device according to claim 1, wherein the material of the vibrating element (160) is sandstone, stone, glass, or wood.

5. The device according to claim 1, wherein a vibration transmission element (150) is arranged between the fluid reservoir and the vibration element (160).

6. The device according to claim 1, wherein the thixotropic fluid is a composite elastomer.

7. The device according to claim 1, wherein the rheopexy fluid is a mixture of lithium hydroxystearate and silicone oil.

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