WO1999056498A1 - Acoustic element - Google Patents

Acoustic element Download PDF

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Publication number
WO1999056498A1
WO1999056498A1 PCT/FI1999/000337 FI9900337W WO9956498A1 WO 1999056498 A1 WO1999056498 A1 WO 1999056498A1 FI 9900337 W FI9900337 W FI 9900337W WO 9956498 A1 WO9956498 A1 WO 9956498A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
acoustic element
porous layer
support points
layers
Prior art date
Application number
PCT/FI1999/000337
Other languages
French (fr)
Inventor
Kari Kirjavainen
Original Assignee
Panphonics Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Panphonics Oy filed Critical Panphonics Oy
Priority to EP99919295A priority Critical patent/EP1060637B1/en
Priority to JP2000546549A priority patent/JP4527282B2/en
Priority to AU37120/99A priority patent/AU3712099A/en
Priority to AT99919295T priority patent/ATE301382T1/en
Priority to CA002330377A priority patent/CA2330377A1/en
Priority to DE69926487T priority patent/DE69926487T2/en
Publication of WO1999056498A1 publication Critical patent/WO1999056498A1/en
Priority to NO20005393A priority patent/NO20005393L/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • H04R7/10—Plane diaphragms comprising a plurality of sections or layers comprising superposed layers in contact
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
    • H04R2201/02—Details casings, cabinets or mounting therein for transducers covered by H04R1/02 but not provided for in any of its subgroups
    • H04R2201/021—Transducers or their casings adapted for mounting in or to a wall or ceiling

Definitions

  • the invention relates to an acoustic element which comprises an arbitrary number of layers, at least one layer comprising at least one porous layer which is either electrically conductive or coated at least on one of its surfaces to be electrically conductive, and at least one film, which is either charged or provided with at least one electrically conductive surface, at least one porous layer and film being arranged to come into contact with each other substantially only at support points, thereby providing an air gap between the porous layer and the film.
  • WO publication 97/31506 discloses a plate-like acoustic element comprising fixed stator plates, with a film secured between the plates at predetermined support points. Between the stator plate and the film are left small air gaps that allow the film 3 to move.
  • the stator plates and the film are provided with electrically conductive surfaces, so by applying electric signals to the surfaces, the film 3 can be made to move to produce sound.
  • the structure is simple and has a very even frequency response, but its field of application is somewhat limited and, to produce a sufficiently high air pressure by using a moving film, a fairly strong electric field is required.
  • An object of the present invention is to provide an acoustic element allowing the above shortcomings to be avoided.
  • the acoustic element of the invention is characterized in that the support points are arranged in such a way that the acoustic element can change its thickness substantially entirely.
  • An essential idea of the invention is that the acoustic element comprises an arbitrary number of layers, at least one layer comprising a porous layer and a film arranged at a distance from the layer, the porous layer and the film coming into contact with each other substantially only at specific support points.
  • the porous layer is either electrically conductive or coated at least on one of its surfaces to be electrically conductive, and the film is charged or provided with at least one electrically conductive surface.
  • the support points at which the film and the porous layer come into contact with each other are arranged in such a way that the entire structure can change its thickness.
  • a preferred embodiment is based on the idea that the acoustic element is coated with an elastic surface material. Another preferred embodiment is based on the idea that the acoustic element is hermetically sealed.
  • An advantage of the invention is that the structure of the acoustic element is very light, solid, inexpensive and easy to manufacture. Further, because the gap between the porous layer and the film is fairly small, a reasonably high pressure is obtained by applying a fairly low control voltage.
  • the porous material provides the element with a large air capacity, whereby the air displaced by the film is able to enter the porous layer, which reduces counter pressure and increases movement. The air entering the porous layer causes flow losses and therefore the structure does not resonate strongly. Further, due to the flow losses the material of the element also attenuates sound passively.
  • An element coated with an elastic surface material can be used for a number of different applications (e.g. floors). Hermetic sealing of the element allows it to be used also in fairly humid conditions.
  • Figure 1 is a schematic sectional side view of an acoustic element of the invention
  • Figure 2 is a schematic sectional side view of another acoustic element of the invention.
  • Figure 3 is a schematic view of a third embodiment of the invention.
  • FIG. 1 shows an acoustic element 1 comprising a plural number of porous layers 2.
  • a typical porous layer is, for example, 0.5 to 1 mm thick, about 70% of the layer being air.
  • the porous layer 2 can be made of cellulose, glass fibre, mineral fibre, metal fibre or by sintering plastic or metal powder.
  • the porous layer 2 is either electrically conductive or coated at least on one of its surfaces to be electrically conductive, for example, by sputtering the surface to provide a metallization 3 thereon.
  • the metallization 3 of the porous layer 2 is typically about 40 nanometers thick.
  • the metallization 3 on the porous layer 2 is also porous in order to allow air to pass through the porous layer 2 and the metallization 3.
  • the acoustic element 1 further comprises a film 4 arranged between the porous layers 2.
  • the porous layer 2 and the film 4 come into contact with each other only at support points 5, an air gap 6 being thus formed between the porous layer 2 and the film 4.
  • the thickness of the film 4 is typically about 5 micrometers and the width of the air gap 6, correspondingly, about 10 micrometers.
  • Figure 1 shows an embodiment in which two films 4 are arranged one on the other, a metallization 7 typically about 40 nanometers thick being arranged between the films.
  • the films are charged and they can be made of polypropylene, polymethyl pentene or cyclic olefin copolymer, for example.
  • the films 4 can be further provided with a bubble structure comprising flat bubbles.
  • Porous layers 2 and films 4 are arranged one on the other to provide the acoustic element 1 with a layered structure as shown in Figure 1.
  • Control electrodes A are connected to the metallizations 7 between the films 4 and earth electrodes B, correspondingly, to the metallizations 3 of the porous layers 2.
  • the support points 5 are arranged in such a way that the film 4 is not supported to the porous layers 2 at exactly the same points on opposite sides of the film. Consequently, when a signal is supplied to the control electrode A, the film 4 changes is form. Since the film 4 is secured to the porous layer 2 at the support point 5, the porous layer 2 also moves and, since the support points 5 are at different places in the acoustic element, the acoustic element 1 can change its thickness substantially entirely.
  • U is voltage acting over the air gap 6, and ⁇ isadielectricity constant of an intermediate medium.
  • the voltage U need not be very high to provide a fairly high pressure P.
  • Figure 2 shows an acoustic element with a plural number of different layers arranged one on the other.
  • Figure 1 shows an acoustic element with a plural number of different layers arranged one on the other.
  • one side of the film 4 is secured substantially entirely to a first porous layer
  • the other side of the film 4 is secured to a second porous layer 2 substantially only at support points 5, between the second porous layer 2 and the film 4 being then the air gap 6.
  • the support points 5 of successive air gaps 6 are at different places, thereby allowing the entire acoustic element to change its thickness.
  • the support points 5 can be formed on the porous plates 2, for example, by pressing the plates at suitable places to form bulges.
  • the places of the support points 5 can vary symmetrically or randomly, but it is essential that the support points 5 of successive layers are arranged at substantially different places.
  • a strong electric field reduces the elastic constant of the structure, i.e. due to pressure the thickness of the structure changes essentially more than without the electric field, thereby substantially increasing the attenuating capability of the structure and lowering its resonance frequency.
  • the structure can function in an attenuating manner, control electronics being not needed then.
  • a static pre-voltage which allows the elastic constant of the structure to be controlled in a desired manner.
  • the films 4 can also be provided with a permanent electret charge, if desired.
  • the pre-voltage can be applied through a resistor having a high resistance, or the control electrode A, for example, can have a high resistance.
  • Figure 3 illustrates the acoustic element 1 coated with an elastic surface material 8.
  • the thickness of the surface material 8 can be from 0.1 to 10mm, for example.
  • the surface material 8 can be a rubber carpet, for example, the acoustic element 1 thus being applicable as a floor covering, for example.
  • the edges of the acoustic element can be provided with sealing portions 9 to make the element 1 hermetically sealed.
  • the control electronics 10 can be arranged inside the acoustic element.
  • the hermetically sealed element 1 can be used in very demanding humid conditions. Further, the acoustic element 1 can be made into a preformed structural board, thereby allowing it to be used as a construction element.
  • the surface material 8 can be substantially air impermeable because the entire acoustic element 1 can change its form and thereby produce sound, although it does not allow air to pass through.
  • the acoustic element in question can be used, for example, for sound attenuating purposes (as floor mats in cars, for example). By increasing the mass of the surface material 8, the attenuating capability of the acoustic element 1 can be enhanced and the resonance frequency further lowered.
  • the acoustic element 1 may comprise an arbitrary number of layers. To produce sound, at least one porous layer 2 and at least one film 4 are needed. Instead of two charged films 4 and the metallization 7 between them shown in the embodiment of Figure 1 , a film with polarized charging can be used (i.e. a film having a positive charging on one side and a negative charging on the other), the control voltage being then applied between the surfaces of the porous layers 2. The film 4 does not have to be charged if at least its surface is electrically conductive.
  • the acoustic element of the invention can be used in various applications relating to sound reproduction and active noise attenuation.
  • the acoustic element, or some of its layers can be used for example as sensors in acoustic systems while, at the same time, the other layers can be used as actuators.

Abstract

The invention relates to an acoustic element comprising and arbitrary number of layers. Each layer comprises at least one porous layer (2) and a film (4) arranged at a distance from the layer. The porous layer (2) can be electrically conductive or coated at least on one of its surfaces to be electrically conductive, and the film (4) can be charged or provided with at least one electrically conductive surface. The porous layer (2) and the film (4) come into contact with each other substantially only at support points (5). The support points (5) are arranged so as to allow the entire structure to change its thickness.

Description

ACOUSTIC ELEMENT
The invention relates to an acoustic element which comprises an arbitrary number of layers, at least one layer comprising at least one porous layer which is either electrically conductive or coated at least on one of its surfaces to be electrically conductive, and at least one film, which is either charged or provided with at least one electrically conductive surface, at least one porous layer and film being arranged to come into contact with each other substantially only at support points, thereby providing an air gap between the porous layer and the film.
WO publication 97/31506 discloses a plate-like acoustic element comprising fixed stator plates, with a film secured between the plates at predetermined support points. Between the stator plate and the film are left small air gaps that allow the film 3 to move. The stator plates and the film are provided with electrically conductive surfaces, so by applying electric signals to the surfaces, the film 3 can be made to move to produce sound. The structure is simple and has a very even frequency response, but its field of application is somewhat limited and, to produce a sufficiently high air pressure by using a moving film, a fairly strong electric field is required. An object of the present invention is to provide an acoustic element allowing the above shortcomings to be avoided.
The acoustic element of the invention is characterized in that the support points are arranged in such a way that the acoustic element can change its thickness substantially entirely. An essential idea of the invention is that the acoustic element comprises an arbitrary number of layers, at least one layer comprising a porous layer and a film arranged at a distance from the layer, the porous layer and the film coming into contact with each other substantially only at specific support points. The porous layer is either electrically conductive or coated at least on one of its surfaces to be electrically conductive, and the film is charged or provided with at least one electrically conductive surface. The support points at which the film and the porous layer come into contact with each other are arranged in such a way that the entire structure can change its thickness. A preferred embodiment is based on the idea that the acoustic element is coated with an elastic surface material. Another preferred embodiment is based on the idea that the acoustic element is hermetically sealed.
An advantage of the invention is that the structure of the acoustic element is very light, solid, inexpensive and easy to manufacture. Further, because the gap between the porous layer and the film is fairly small, a reasonably high pressure is obtained by applying a fairly low control voltage. The porous material provides the element with a large air capacity, whereby the air displaced by the film is able to enter the porous layer, which reduces counter pressure and increases movement. The air entering the porous layer causes flow losses and therefore the structure does not resonate strongly. Further, due to the flow losses the material of the element also attenuates sound passively. An element coated with an elastic surface material can be used for a number of different applications (e.g. floors). Hermetic sealing of the element allows it to be used also in fairly humid conditions.
The invention will be described in greater detail in the accompanying drawings, of which
Figure 1 is a schematic sectional side view of an acoustic element of the invention;
Figure 2 is a schematic sectional side view of another acoustic element of the invention; and Figure 3 is a schematic view of a third embodiment of the invention.
Figure 1 shows an acoustic element 1 comprising a plural number of porous layers 2. A typical porous layer is, for example, 0.5 to 1 mm thick, about 70% of the layer being air. The porous layer 2 can be made of cellulose, glass fibre, mineral fibre, metal fibre or by sintering plastic or metal powder. The porous layer 2 is either electrically conductive or coated at least on one of its surfaces to be electrically conductive, for example, by sputtering the surface to provide a metallization 3 thereon. The metallization 3 of the porous layer 2 is typically about 40 nanometers thick. The metallization 3 on the porous layer 2 is also porous in order to allow air to pass through the porous layer 2 and the metallization 3.
The acoustic element 1 further comprises a film 4 arranged between the porous layers 2. The porous layer 2 and the film 4 come into contact with each other only at support points 5, an air gap 6 being thus formed between the porous layer 2 and the film 4. The thickness of the film 4 is typically about 5 micrometers and the width of the air gap 6, correspondingly, about 10 micrometers. Figure 1 shows an embodiment in which two films 4 are arranged one on the other, a metallization 7 typically about 40 nanometers thick being arranged between the films. The films are charged and they can be made of polypropylene, polymethyl pentene or cyclic olefin copolymer, for example. The films 4 can be further provided with a bubble structure comprising flat bubbles.
Porous layers 2 and films 4 are arranged one on the other to provide the acoustic element 1 with a layered structure as shown in Figure 1. Control electrodes A are connected to the metallizations 7 between the films 4 and earth electrodes B, correspondingly, to the metallizations 3 of the porous layers 2. The support points 5 are arranged in such a way that the film 4 is not supported to the porous layers 2 at exactly the same points on opposite sides of the film. Consequently, when a signal is supplied to the control electrode A, the film 4 changes is form. Since the film 4 is secured to the porous layer 2 at the support point 5, the porous layer 2 also moves and, since the support points 5 are at different places in the acoustic element, the acoustic element 1 can change its thickness substantially entirely.
Pressure P caused by the acoustic element 1 is obtained from the following formula
ε *U2
P = 1/2 s2 where s is the width of the air gap 6,
U is voltage acting over the air gap 6, and ε isadielectricity constant of an intermediate medium.
Since the width s of the air gap 6 in the element concerned is very small, the voltage U need not be very high to provide a fairly high pressure P.
Figure 2 shows an acoustic element with a plural number of different layers arranged one on the other. In the embodiment shown in Figure
2 one side of the film 4 is secured substantially entirely to a first porous layer
2. The other side of the film 4 is secured to a second porous layer 2 substantially only at support points 5, between the second porous layer 2 and the film 4 being then the air gap 6. When the film 4 moves, it also makes the porous layer 2 move to which it is secured. The support points 5 of successive air gaps 6 are at different places, thereby allowing the entire acoustic element to change its thickness.
The support points 5 can be formed on the porous plates 2, for example, by pressing the plates at suitable places to form bulges. The places of the support points 5 can vary symmetrically or randomly, but it is essential that the support points 5 of successive layers are arranged at substantially different places.
A strong electric field reduces the elastic constant of the structure, i.e. due to pressure the thickness of the structure changes essentially more than without the electric field, thereby substantially increasing the attenuating capability of the structure and lowering its resonance frequency. When the control electrodes A and the earth electrodes B are connected with each other, the structure can function in an attenuating manner, control electronics being not needed then. Between the control electrodes A and earth electrodes B can also be applied a static pre-voltage which allows the elastic constant of the structure to be controlled in a desired manner. The films 4 can also be provided with a permanent electret charge, if desired. The pre-voltage can be applied through a resistor having a high resistance, or the control electrode A, for example, can have a high resistance. Figure 3 illustrates the acoustic element 1 coated with an elastic surface material 8. The thickness of the surface material 8 can be from 0.1 to 10mm, for example. The surface material 8 can be a rubber carpet, for example, the acoustic element 1 thus being applicable as a floor covering, for example. The edges of the acoustic element can be provided with sealing portions 9 to make the element 1 hermetically sealed. Also the control electronics 10 can be arranged inside the acoustic element. The hermetically sealed element 1 can be used in very demanding humid conditions. Further, the acoustic element 1 can be made into a preformed structural board, thereby allowing it to be used as a construction element. The surface material 8 can be substantially air impermeable because the entire acoustic element 1 can change its form and thereby produce sound, although it does not allow air to pass through. The acoustic element in question can be used, for example, for sound attenuating purposes (as floor mats in cars, for example). By increasing the mass of the surface material 8, the attenuating capability of the acoustic element 1 can be enhanced and the resonance frequency further lowered.
The drawings and the related description are only meant to illustrate 5 the inventive idea. The details of the invention may vary within the scope of the claims. The acoustic element 1 may comprise an arbitrary number of layers. To produce sound, at least one porous layer 2 and at least one film 4 are needed. Instead of two charged films 4 and the metallization 7 between them shown in the embodiment of Figure 1 , a film with polarized charging can be used (i.e. a film having a positive charging on one side and a negative charging on the other), the control voltage being then applied between the surfaces of the porous layers 2. The film 4 does not have to be charged if at least its surface is electrically conductive. The acoustic element of the invention can be used in various applications relating to sound reproduction and active noise attenuation. The acoustic element, or some of its layers, can be used for example as sensors in acoustic systems while, at the same time, the other layers can be used as actuators.

Claims

6CLAIMS
1. An acoustic element which comprises an arbitrary number of layers, at least one layer comprising at least one porous layer (2) which is either electrically conductive or coated at least on one of its surfaces to be electrically conductive, and at least one film (4), which is either charged or provided with at least one electrically conductive surface, at least one porous layer (2) and film (4) being arranged to come into contact with each other substantially only at support points (5), thereby providing an air gap between the porous layer (2) and the film (4), characterized in that the support points (5) are arranged in such a way that the acoustic element (1) can change its thickness substantially entirely.
2. An acoustic element according to claim 1, characterized in that the element (1) comprises at least two porous elements (2), at least one film (4) being arranged between the layers in such a way that on both sides of the film (4), an air gap (6) is formed, the support points (5) on opposite sides of the film (4) being arranged at substantially different places.
3. An acoustic element according to claim 1, characterized in that the element (1) comprises at least two porous layers (2), at least one film (4) being arranged between the layers in such a way that the film (4) is secured to a second porous layer (2) and between the second porous layer (2) and the film (4) is an air gap (6).
4. An acoustic element according to claim 3, characterized in that the acoustic element (1) is a layered structure comprising at least two air gaps (6) arranged one on the other, the support points (5) in successive air gaps (6) being substantially at different places.
5. An acoustic element according to any one of preceding claims, characterized in that the acoustic element (1) is coated with an elastic surface material (8).
6. An acoustic element according to claim 5, characterized in that the acoustic element (1) is hermetically sealed.
PCT/FI1999/000337 1998-04-27 1999-04-26 Acoustic element WO1999056498A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
EP99919295A EP1060637B1 (en) 1998-04-27 1999-04-26 Acoustic element
JP2000546549A JP4527282B2 (en) 1998-04-27 1999-04-26 Acoustic element
AU37120/99A AU3712099A (en) 1998-04-27 1999-04-26 Acoustic element
AT99919295T ATE301382T1 (en) 1998-04-27 1999-04-26 ACOUSTIC ELEMENT
CA002330377A CA2330377A1 (en) 1998-04-27 1999-04-26 Acoustic element
DE69926487T DE69926487T2 (en) 1998-04-27 1999-04-26 ACOUSTIC ELEMENT
NO20005393A NO20005393L (en) 1998-04-27 2000-10-26 Acoustic element

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI980926A FI115598B (en) 1998-04-27 1998-04-27 Acoustic element
FI980926 1998-04-27

Publications (1)

Publication Number Publication Date
WO1999056498A1 true WO1999056498A1 (en) 1999-11-04

Family

ID=8551595

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1999/000337 WO1999056498A1 (en) 1998-04-27 1999-04-26 Acoustic element

Country Status (9)

Country Link
EP (1) EP1060637B1 (en)
JP (1) JP4527282B2 (en)
AT (1) ATE301382T1 (en)
AU (1) AU3712099A (en)
CA (1) CA2330377A1 (en)
DE (1) DE69926487T2 (en)
FI (1) FI115598B (en)
NO (1) NO20005393L (en)
WO (1) WO1999056498A1 (en)

Cited By (14)

* Cited by examiner, † Cited by third party
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WO2002085065A1 (en) * 2001-04-11 2002-10-24 Panphonics Oy Electromechanical transducer and method for transforming energies
US6873863B2 (en) 2001-03-19 2005-03-29 Nokia Mobile Phones Ltd. Touch sensitive navigation surfaces for mobile telecommunication systems
WO2005072006A1 (en) * 2004-01-22 2005-08-04 Oy North Wave Ltd Loudspeaker
WO2006037586A1 (en) * 2004-10-04 2006-04-13 Volkswagen Ag Loud speaker arrangement in a motor vehicle
DE102005058175A1 (en) * 2005-12-05 2007-06-06 Volkswagen Ag Speaker arrangement for sound in a motor vehicle
WO2007098916A1 (en) * 2006-03-01 2007-09-07 Volkswagen Aktiengesellschaft Loudspeaker arrangement in a motor vehicle, and a method for actuating the at least one loudspeaker
EP1868412A2 (en) 2006-06-13 2007-12-19 Volkswagen Aktiengesellschaft Speaker assembly for directional sonification of a motor vehicle seat
WO2008102063A1 (en) 2007-02-23 2008-08-28 Panphonics Oy Acoustic actuator plate structure
DE102007063344A1 (en) 2007-12-28 2009-07-02 S1Nn Gmbh & Co. Kg Audio output stage for electrostatic flat surface loudspeaker in motor vehicle, has matching circuit including transformer and arranged between audio output stage for electrodynamic loudspeaker and electrostatic flat surface loudspeaker
US7589439B2 (en) 2002-01-17 2009-09-15 B-Band Oy Electromechanical transducer element, method for forming an electromechanical transducer element and transducer formed by said method
DE102008047796A1 (en) 2008-09-17 2010-04-15 Siemens Aktiengesellschaft Device for generating broadband sound in the audible range of humans
US10362405B2 (en) 2014-10-16 2019-07-23 Yamaha Coporaration Fixed electrode and electroacoustic transducer
TWI708473B (en) * 2019-09-27 2020-10-21 華碩電腦股份有限公司 Actuator
CN112584290A (en) * 2019-09-27 2021-03-30 华硕电脑股份有限公司 Actuator

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JP2006148612A (en) * 2004-11-22 2006-06-08 Yamaha Corp Acoustic device
DE102007007957A1 (en) * 2007-02-17 2008-08-21 Lyttron Technology Gmbh Loudspeaker constructed of foils

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Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6873863B2 (en) 2001-03-19 2005-03-29 Nokia Mobile Phones Ltd. Touch sensitive navigation surfaces for mobile telecommunication systems
US7376239B2 (en) 2001-04-11 2008-05-20 Panphonics Oy Electromechanical transducer and method for transforming energies
WO2002085065A1 (en) * 2001-04-11 2002-10-24 Panphonics Oy Electromechanical transducer and method for transforming energies
US7589439B2 (en) 2002-01-17 2009-09-15 B-Band Oy Electromechanical transducer element, method for forming an electromechanical transducer element and transducer formed by said method
WO2005072006A1 (en) * 2004-01-22 2005-08-04 Oy North Wave Ltd Loudspeaker
WO2006037586A1 (en) * 2004-10-04 2006-04-13 Volkswagen Ag Loud speaker arrangement in a motor vehicle
US8848938B2 (en) 2004-10-04 2014-09-30 Volkswagen Ag Electrostatic planar loudspeaker arrangement in a motor vehicle
DE102005058175A1 (en) * 2005-12-05 2007-06-06 Volkswagen Ag Speaker arrangement for sound in a motor vehicle
WO2007098916A1 (en) * 2006-03-01 2007-09-07 Volkswagen Aktiengesellschaft Loudspeaker arrangement in a motor vehicle, and a method for actuating the at least one loudspeaker
WO2007101462A1 (en) * 2006-03-01 2007-09-13 Volkswagen Aktiengesellschaft Loudspeaker arrangement in a motor vehicle, and a method for driving the at least one loudspeaker
EP1868412A2 (en) 2006-06-13 2007-12-19 Volkswagen Aktiengesellschaft Speaker assembly for directional sonification of a motor vehicle seat
DE102006049543A1 (en) * 2006-06-13 2007-12-20 Volkswagen Ag Speaker arrangement for directional sonication of a motor vehicle seat
WO2008102063A1 (en) 2007-02-23 2008-08-28 Panphonics Oy Acoustic actuator plate structure
EP2121302A1 (en) * 2007-02-23 2009-11-25 Panphonics Oy Acoustic actuator plate structure
EP2121302A4 (en) * 2007-02-23 2011-12-14 Panphonics Oy Acoustic actuator plate structure
US9301055B2 (en) 2007-02-23 2016-03-29 Panphonics Oy Acoustic actuator plate structure
DE102007063344A1 (en) 2007-12-28 2009-07-02 S1Nn Gmbh & Co. Kg Audio output stage for electrostatic flat surface loudspeaker in motor vehicle, has matching circuit including transformer and arranged between audio output stage for electrodynamic loudspeaker and electrostatic flat surface loudspeaker
DE102008047796A1 (en) 2008-09-17 2010-04-15 Siemens Aktiengesellschaft Device for generating broadband sound in the audible range of humans
US10362405B2 (en) 2014-10-16 2019-07-23 Yamaha Coporaration Fixed electrode and electroacoustic transducer
TWI708473B (en) * 2019-09-27 2020-10-21 華碩電腦股份有限公司 Actuator
CN112584290A (en) * 2019-09-27 2021-03-30 华硕电脑股份有限公司 Actuator
CN112584290B (en) * 2019-09-27 2022-07-26 华硕电脑股份有限公司 Actuator
US11799395B2 (en) 2019-09-27 2023-10-24 Asustek Computer Inc. Actuator

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AU3712099A (en) 1999-11-16
EP1060637A1 (en) 2000-12-20
FI980926A0 (en) 1998-04-27
NO20005393D0 (en) 2000-10-26
CA2330377A1 (en) 1999-11-04
DE69926487D1 (en) 2005-09-08
EP1060637B1 (en) 2005-08-03
DE69926487T2 (en) 2006-05-18
NO20005393L (en) 2000-10-26
FI115598B (en) 2005-05-31
FI980926A (en) 1999-10-28
JP2002513263A (en) 2002-05-08
JP4527282B2 (en) 2010-08-18
ATE301382T1 (en) 2005-08-15

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