WO1999062295A1 - Panneau acoustique - Google Patents

Panneau acoustique Download PDF

Info

Publication number
WO1999062295A1
WO1999062295A1 PCT/GB1999/001647 GB9901647W WO9962295A1 WO 1999062295 A1 WO1999062295 A1 WO 1999062295A1 GB 9901647 W GB9901647 W GB 9901647W WO 9962295 A1 WO9962295 A1 WO 9962295A1
Authority
WO
WIPO (PCT)
Prior art keywords
panel
core
honeycomb
skin
mpa
Prior art date
Application number
PCT/GB1999/001647
Other languages
English (en)
Inventor
Michael Sacks
Peter Sajic
William Zuill
Original Assignee
Michael Sacks
Peter Sajic
William Zuill
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
Priority claimed from GBGB9811522.3A external-priority patent/GB9811522D0/en
Priority claimed from GBGB9822125.2A external-priority patent/GB9822125D0/en
Application filed by Michael Sacks, Peter Sajic, William Zuill filed Critical Michael Sacks
Priority to AU40517/99A priority Critical patent/AU4051799A/en
Publication of WO1999062295A1 publication Critical patent/WO1999062295A1/fr

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

Definitions

  • the present invention relates to an acoustic panel and to a method of manufacturing an acoustic panel.
  • Flat panel loudspeakers have recently become available. Unlike traditional loudspeakers, they do not have a conical diaphragm, but instead have a planar element driven by a transducer. In general, the planar element should be stiff, but this alone is not sufficient and such panels have been found to produce a sound that can exhibit unwanted peaks in the audible response.
  • Flat panel speakers hereinbefore have been made from thermoset composite skins bonded to aluminium honeycomb cores and foam cores. Such panels have not produced a high quality response over the audible range and are also expensive to manufacture.
  • an acoustic panel comprising an inner low density core layer and outer stiff skin layers attached each side of the core layer so as to form a rigid panel.
  • the panel and/or the skin layers have a specific stiffness E/p to produce the desired acoustic properties, where E is the Young's Modulus and p is the mass density of the panel.
  • the three layers are brought together as preformed layers that are attached in a lamination process, and are preferably thermoplastic materials which are fused together by the application of heat and pressure in the lamination process.
  • the core layer comprises a thermoplastic dry film, such as a polyethyl terephthalate (PET) extruded or blown film of low weight but high bulk, in the form of a cellular structure.
  • a thermoplastic dry film such as a polyethyl terephthalate (PET) extruded or blown film of low weight but high bulk, in the form of a cellular structure.
  • PET polyethyl terephthalate
  • this film is 0.15mm thick with a density of 120gm/m 2 , or is 0.3mm thick with a density of 240gm/m 2 , and is used as a single layer or in multiples to form the core layer.
  • the film density might range from 20 to 480gm/m 2 .
  • the skin layers comprise a woven glass cloth impregnated with polycarbonate.
  • This is very thin and is typically 0.075mm thick and has a density of lOOgm/m 2 , although the film density might range from 20 to 200gm/m 2 .
  • the mechanical properties of the skin layer are typically an elastic modulus Ex 13-21 Gpa, an elastic modulus Ey 13-21 Gpa, a shear modulus Gxy 3-4 Gpa, a Poissons Ratio Uxy 0.1-0.3, a Tensile Strength 320-370 Mpa, a Compressive Strength 280-320 Mpa, a Flexural Strength 430-540 Mpa and an In Plane Shear Strength 40-53 Mpa.
  • the core layer may comprise a honeycomb layer.
  • a damping film is disposed between the core and the skin layers.
  • the honeycomb core has a shear modulus greater than 28Mpa. This has been found to provide acceptable performance within flat loudspeakers.
  • the term "honeycomb" is to be construed broadly as at to include multicelled layers whether on not the cells share common walls and irrespective of cell shape.
  • the honeycomb core is formed of thermoplastic, such as polycarbonate, polyethersulphone, polyetherimide and/or other amorphous thermoplastics.
  • thermoplastic such as polycarbonate, polyethersulphone, polyetherimide and/or other amorphous thermoplastics.
  • the outermost skins are made of thermoplastic.
  • the skins may be made of polycarbonate, polyester or other amorphous thermoplastics. These thermoplastics may be provided in the form of unreinforced films.
  • the damping films are formed from polyamide, polyurethane, polyester, polypropylene or polyethylene.
  • a honeycomb element comprising a plurality of cells separated by dividing walls, wherein the walls have been distorted by heat and pressure such that some of the walls are buckled.
  • the honeycomb may be manufactured by arranging a plurality of tubes into an array. Preferably the tubes are close packed. Thus each tube within the body of the array has six touching neighbours. This results in an arrangement comprising large cells as defined by the tubes themselves and small cells formed by the spaces between the tubes.
  • the tubes may then be heated under pressure so as to deform the ends of the tubes. This deformation gives rise to two changes in the construction of the panel. Firstly the bond area between the core and the damping film is increased. This results in panels which, in comparative tests, sound better. Secondly the wall profile becomes changed such that the ends of the tubes become hexagonal, whereas the central portions of the tubes remain approximately circular. This causes the small cells to become closed at their ends. This also gives rise to a perceived improvement in sound quality.
  • a method of manufacturing the panel according to the first aspect of the invention comprising fusing the core to the skin under melt temperature and pressure.
  • Such a panel can be made on a continuous basis and at a price which makes it affordable. Tests have demonstrated that a belt press can produce 18m 2 /min of the panel. The panel is also visually acceptable for use in the mass consumer market.
  • the honeycomb core may, advantageously, be reduced in thickness. Reductions of 5 to 15% have been used in trials with a polycarbonate honeycomb core, although other core materials may give their best results with reductions falling outside of this range.
  • Figure 1 schematically shows a cross section through a panel constituting an embodiment of the present invention
  • Figure 2 schematically shows a cross-section through the honeycomb core along the line A- A of Figure 1;
  • Figure 3 schematically shows a cross section through the honeycomb core along the line B- B of Figure 1;
  • Figure 4 shows a comparison between a panel constituting an embodiment of the present invention, and a similar panel in which the damping films have been omitted;
  • Figure 5 shows the acoustic performance of another panel constituting a further embodiment of the present invention.
  • the panel shown in figure 1 comprises a skin 2, of woven glass-polycarbonate with a weight of 160 grams per square metre and layer directions at +/- 45 degrees.
  • a first damping film 4 is bonded to the skin 2 and also to a honeycomb core 6.
  • the damping film is a polyamide layer having a weight of 60 grams per square metre.
  • the honeycomb core is a polycarbonate layer, typically between 3 and 7mm thick, having a 6mm cell diameter and a density of around 70 Kg/m 3 .
  • Overlying the core 6 is a second damping film 8 and a second skin 10 identical to the damping film 4 and skin 2, respectively.
  • Such a panel has a low mass per unit area and therefore reduces the load on the exciter required to vibrate it. However such a panel also exhibits high specific stiffness.
  • the panel is manufactured in such a way that the honeycomb core has controlled distortions introduced therein.
  • the honeycomb core initially is in the form of a plurality of tubes closely packed together. This results in an arrangement like that shown in Figure 2.
  • the tubes 20 touch one another, and in so doing define interstitial triangular regions 22 bounded by curved walls.
  • the components of the panel i.e. honeycomb core, dampening films and skins, are pressed together and heated.
  • the heating and compression can be performed on a continuous basis using a belt press.
  • a production line can be used to produce the panel on a continuous rather than a batch basis.
  • a honeycomb core of 7mm thickness and bounded on either side by damping film and skin passes between heated rollers set to reduce the panel thickness to 6.3 to 6.5mm by applying a pressure of approximately 15 pounds per square inch (1 x 10 5 Pa) at a temperature of 150°C. This causes the honeycomb to deform so as to increase the contact area with the damping film and to close the interstitial regions.
  • the edge of the deformed honeycomb is illustrated in Figure 3.
  • the inclusion of the damping films prevent the panel from ringing. This phenomena results from the requirement to have low mass and high stiffness, and also the inclusion of air spaces in the cells.
  • the damping film alleviates the ringing of the panel.
  • the film properties and weight, i.e. weight per unit area, can be varied to tailor the frequency response of the panel. In tests, the inventors have been able to tailor the frequency response of the panel between 0 and 12 kHz .
  • the damping film works by attenuating vibrations from the skins to the core and hence controls unwanted noise, the damping film has to satisfy three important conditions.
  • the storage modulus and loss factor must be correct, and the film must be fusible to both the skin and the core.
  • the storage modulus is a measure of the dynamic elastic stiffness of the material and the loss factor is a measure of the dissipation of vibrational energy per cycle of material. Films that have a high loss factor and a low storage modulus are desirable in the panel.
  • Figure 4 compares the frequency performance of a panel without the damping films, as indicated by line 12, with a similar panel but including the damping film, as indicated by line 14.
  • the panel tested was designed for high frequency use in the range above 3 kHz.
  • the panel 14 has a smoother frequency response that the undampened panel 12.
  • An acoustic panel according to the invention can be made on a continuous basis, for example, using a belt press to compress the layers together whilst they are heated, and can thereby produce panel at a rate typically of the order of 18m 2 /minute.
  • the acoustic performance of a panel constituting a further embodiment of the invention is in Figure 5.
  • the panel comprises a single layer core of PET of 250gm/m 2 and outer skins of woven glass cloth/polycarbonate 0.075mm thick, the overall thickness being 0.5mm and the overall density being 560gm/m 2 .
  • a sample of panel 30cm 2 was used and the magnitude of its frequency response was measured over the range 200Hz to 20Khz.
  • Other panels according to the invention might range in overall thickness from 0.3mm to 0.85mm, and have an overall density from 480 to 960gm/m 2 .
  • the central core may comprise a polyester based thermoplastic adhesive web such as that sold under the trademark SHARNET SH4275 having the following properties:
  • SH4275 gives excellent bonds with various substrates, and it will bond to PVC films and foams, polyester textiles and films, polyethylene and polyurethane foams, polyamide textiles, cellulosics, ABS, polycarbonate and glass fibre.
  • the central core may be composed of other thermoplastic blown film materials, such as polyurethane, polyamide, polypropylene and polyolyephin.
  • the outer skin layer may be composed of a woven glass cloth impregnated with phenolic or polyetherimide.
  • other combinations of reinforcing fibre and impregnated plastics material can be used, such as fibre matrices of carbon, Kevlar, nylon or polyester, and impregnation with polyethersulphone, polyetherketone, polysulphone, polyamide and PET.
  • the outer skin layers may also be composed of thermoset materials rather than thermoplastics materials, but this would effect the manufacturing process, which would not then fuse the layers together, but would rather make use of an adhesive.
  • Acoustic panels according to the invention are especially suitable for smaller speakers, say smaller than 8in x 5in, for example, speakers for mobile telephones.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Laminated Bodies (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)

Abstract

L'invention porte sur un panneau acoustique dans lequel une âme (6) légère présentant une structure cellulaire est disposée entre des enveloppes (2, 10) rigides. Un film d'amortissement peut être ménagé entre chaque enveloppe et l'âme.
PCT/GB1999/001647 1998-05-28 1999-05-26 Panneau acoustique WO1999062295A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU40517/99A AU4051799A (en) 1998-05-28 1999-05-26 Acoustic panel

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
GBGB9811522.3A GB9811522D0 (en) 1998-05-28 1998-05-28 Acoustic panel
GB9811522.3 1998-05-28
GBGB9814168.2A GB9814168D0 (en) 1998-05-28 1998-06-30 Acoustic panel
GB9814168.2 1998-06-30
GB9822125.2 1998-10-09
GBGB9822125.2A GB9822125D0 (en) 1998-10-09 1998-10-09 Acoustic panel

Publications (1)

Publication Number Publication Date
WO1999062295A1 true WO1999062295A1 (fr) 1999-12-02

Family

ID=27269333

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/001647 WO1999062295A1 (fr) 1998-05-28 1999-05-26 Panneau acoustique

Country Status (2)

Country Link
AU (1) AU4051799A (fr)
WO (1) WO1999062295A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8573357B1 (en) 2012-12-07 2013-11-05 Eggers Industries, Inc. Acoustical door
WO2015031684A1 (fr) * 2013-08-28 2015-03-05 StudioFeed USA, LLC Dispositif sonore tactile à plusieurs étages
US10152296B2 (en) 2016-12-28 2018-12-11 Harman International Industries, Incorporated Apparatus and method for providing a personalized bass tactile output associated with an audio signal
IT201700081708A1 (it) * 2017-07-19 2019-01-19 Furio Bianchi Pannello composito in policarbonato alveolare rivestito da foglio di laminato
IT201800010199A1 (it) * 2018-11-09 2020-05-09 Renolit Gor Spa Carrello in particolare per la gestione di pacchi o simili

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4047060A (en) * 1971-09-07 1977-09-06 Motorola, Inc. Acoustic transducer with elastomeric coupling
US4291205A (en) * 1978-09-19 1981-09-22 Sony Corporation Laminated loudspeaker diaphragm with honeycomb core and damping layers
JPS5779797A (en) * 1980-11-04 1982-05-19 Mitsubishi Electric Corp Diaphragm for speaker and its manufacture
US4353947A (en) * 1981-10-05 1982-10-12 International Harvester Co. Laminated composite structure and method of manufacture
JPS58153492A (ja) * 1982-03-08 1983-09-12 Mitsubishi Electric Corp スピ−カ用振動板およびその製造方法
EP0322587A2 (fr) * 1987-12-01 1989-07-05 Kabushiki Kaisha Kenwood Diaphragme pour haut-parleur
JPH04294136A (ja) * 1991-03-25 1992-10-19 Toray Ind Inc ハニカムサンドイッチパネルの製造方法
JPH08305369A (ja) * 1995-05-09 1996-11-22 Toray Ind Inc 遮音・制振材用フィルムおよびそれを用いた遮音・制振材

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4047060A (en) * 1971-09-07 1977-09-06 Motorola, Inc. Acoustic transducer with elastomeric coupling
US4291205A (en) * 1978-09-19 1981-09-22 Sony Corporation Laminated loudspeaker diaphragm with honeycomb core and damping layers
JPS5779797A (en) * 1980-11-04 1982-05-19 Mitsubishi Electric Corp Diaphragm for speaker and its manufacture
US4353947A (en) * 1981-10-05 1982-10-12 International Harvester Co. Laminated composite structure and method of manufacture
JPS58153492A (ja) * 1982-03-08 1983-09-12 Mitsubishi Electric Corp スピ−カ用振動板およびその製造方法
EP0322587A2 (fr) * 1987-12-01 1989-07-05 Kabushiki Kaisha Kenwood Diaphragme pour haut-parleur
JPH04294136A (ja) * 1991-03-25 1992-10-19 Toray Ind Inc ハニカムサンドイッチパネルの製造方法
JPH08305369A (ja) * 1995-05-09 1996-11-22 Toray Ind Inc 遮音・制振材用フィルムおよびそれを用いた遮音・制振材

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 17, no. 103 (M - 1374) 2 March 1993 (1993-03-02) *
PATENT ABSTRACTS OF JAPAN vol. 6, no. 160 (E - 126) 21 August 1982 (1982-08-21) *
PATENT ABSTRACTS OF JAPAN vol. 7, no. 272 (E - 214) 3 December 1983 (1983-12-03) *
PATENT ABSTRACTS OF JAPAN vol. 97, no. 3 31 March 1997 (1997-03-31) *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8573357B1 (en) 2012-12-07 2013-11-05 Eggers Industries, Inc. Acoustical door
WO2015031684A1 (fr) * 2013-08-28 2015-03-05 StudioFeed USA, LLC Dispositif sonore tactile à plusieurs étages
US9672703B2 (en) 2013-08-28 2017-06-06 Subpac, Inc. Multistage tactile sound device
US10111010B2 (en) 2013-08-28 2018-10-23 Subpac, Inc. Multistage tactile sound device
US10812914B2 (en) 2013-08-28 2020-10-20 Subpac, Inc. Multistage tactile sound device
US10152296B2 (en) 2016-12-28 2018-12-11 Harman International Industries, Incorporated Apparatus and method for providing a personalized bass tactile output associated with an audio signal
US10620906B2 (en) 2016-12-28 2020-04-14 Harman International Industries, Incorporated Apparatus and method for providing a personalized bass tactile output associated with an audio signal
IT201700081708A1 (it) * 2017-07-19 2019-01-19 Furio Bianchi Pannello composito in policarbonato alveolare rivestito da foglio di laminato
WO2019016713A1 (fr) * 2017-07-19 2019-01-24 Bianchi Furio Panneau composite constitué d'une feuille de polycarbonate à parois multiples recouverte d'une couche stratifiée
CN110944833A (zh) * 2017-07-19 2020-03-31 弗里奥·比安奇 由层压层覆盖的聚碳酸酯多壁片材制成的复合面板
IT201800010199A1 (it) * 2018-11-09 2020-05-09 Renolit Gor Spa Carrello in particolare per la gestione di pacchi o simili

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