Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/08—Mouthpieces; Microphones; Attachments therefor
  • H04R1/083—Special constructions of mouthpieces
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/222—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only  for microphones
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R2460/00—Details of hearing devices, i.e. of ear- or headphones covered by H04R1/10 or H04R5/033 but not provided for in any of their subgroups, or of hearing aids covered by H04R25/00 but not provided for in any of its subgroups
  • H04R2460/13—Hearing devices using bone conduction transducers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R5/00—Stereophonic arrangements
  • H04R5/033—Headphones for stereophonic communication

Definitions

• the present invention relates to an acoustic device of the type comprising an acoustic contact microphone and a microphone holding bar resting on a side flank of the skull, said microphone comprising a housing and a bone mechanical excitation transducer disposed in the housing, said transducer being able to receive by bone conduction a sound signal from the vocal cords, said housing having a bearing wall on an area of the cheek.
• the invention also relates to an operator head equipment comprising a protective helmet and such an acoustic device.
• the microphone transducer detects mechanical vibratory waves of a sound signal coming from the vocal cords, the vibratory waves being transmitted by bone conduction through the mandible bone of a human skull. .
• the microphone transducer is adapted to transform the detected mechanical vibratory waves into an electrical signal, which is transmitted to a communication system by a connecting cable.
• the electrical signal corresponding to the initial sound signal and transmitted by the acoustic device to the communication system is difficult to understand.
• the consonants / vowels / consonants (CVC) rate which measures the recognition rate of consonants and vowels in a sound sequence, is significantly less than 50% with such an acoustic device.
• This low rate reflects the difficulty of listening to an electrical signal from the acoustic device.
• the transducer ensures a correct transformation of the mechanical signal into an electrical signal and the low CVC rate results more particularly from a deformation of the vibratory waves of the sound signal during their path between the vocal cords and the transducer.
• the object of the invention is therefore to allow a better quality of listening of the signal from the acoustic device, and in particular to increase the value of the CVC rate for a sound signal transmitted by this device.
• the subject of the invention is therefore an acoustic device of the aforementioned type, characterized in that the wall is in the form of a skin in contact with the transducer of the microphone, and in that the wall has a hardness between 45 and 85 Shore A and a thickness of between 0.4 and 0.6 mm.
• the acoustic device comprises one or more of the following characteristics, taken separately or in any technically possible combination:
• the hardness of the wall is between 55 and 80 Shore A, preferably between 65 and 75 Shore A;
• the wall is integral with a protective envelope of the transducer of the contact microphone;
• the transducer of the contact microphone is an accelerometer;
• the transducer of the contact microphone is immobilized in the housing
• the housing comprises a protective mass of the transducer of the contact microphone, on the opposite side to the support wall;
• the housing is made of synthetic rubber; the acoustic microphone is able to bear on the mandibular bone, also called the lower jawbone;
• the device comprises two lateral acoustic modules resting on the lateral flanks of the skull and capable of transmitting a sound signal to the auditory nerve;
• the lateral acoustic modules each comprise a bone mechanical excitation transducer capable of transmitting a sound signal to the auditory nerve by bone conduction, and are interconnected by at least one connecting arch;
• the microphone is connected to a corresponding acoustic module, and the device comprises acoustic decoupling means between the microphone and the module to which the microphone is connected;
• the microphone is connected to the corresponding acoustic module by two connecting arms, and the spacing between the outer and opposite edges of the two connecting arms is progressively increasing from the microphone towards the acoustic module; , to allow attenuation of sound mechanical waves propagating from the microphone to the corresponding acoustic module;
• the device is, by its dimensions, suitable for use with a heavy infantryman's helmet or with a chemical bacteriological nuclear mask.
• the invention also relates to a head gear for operator comprising a protective helmet, characterized in that it comprises an acoustic device as defined above.
• FIG. 1 is an overall perspective view of an acoustic device according to the invention
• FIG. 2 is a front view of a microphone of the acoustic device according to the invention.
• FIG. 3 is a sectional view along plane III of FIG. 2,
• FIG. 4 is a sectional view along plane IV of FIG. 2,
• FIG. 5 is a sectional view along plane V of FIG. 2, and
• an acoustic device 2 comprises an acoustic microphone 4 of contact connected to one of the two side acoustic modules 6.
• the acoustic device 2 also comprises an upper arch 8, a rear arch 10 connecting the acoustic modules 6, and a connection cable 12.
• the upper arch 8 also called headband 8, is of adjustable length and adapted to be positioned on the top of the head.
• the rear arch 10 made of a rigid material, is a mechanical support bar of the microphone 4 resting on the mandible bone and each module 6 bears on a corresponding lateral side of the skull.
• the support bar 10 is of adjustable length, and able to be positioned under the bone of the rock behind the head, near the neck.
• the contact microphone 4 comprises a bone mechanical excitation transducer 14, visible in FIGS. 5 and 6, disposed in a protective housing 16.
• the housing 16 is connected to a corresponding acoustic module 6 by two connecting arms 18.
• the transducer 14 of the microphone is a clean accelerometer to receive by bone conduction, in particular through the mandible bone of the skull, the vibratory waves of a sound signal from the vocal cords and to transform them into an electrical signal.
• the housing 16 has a bearing wall 20 on an area of the cheek and an external mass 22 for protecting the accelerometer 14 of the contact microphone, on the opposite side to the support wall 20, as shown in FIGS. and 6.
• the housing 16 is made of synthetic rubber.
• the wall 20 is in the form of a skin in contact with the accelerometer 14 of the microphone.
• the skin 20, visible in section in FIGS. 5 and 6, has a value hardness of between 45 and 85 shores A, so that the skin 20 has a mechanical impedance substantially equal to the mechanical impedance of the cheek.
• the value of the hardness of the skin 20 is preferably between 55 and 80 Shore A, more preferably between 65 and 75 Shore A.
• the thickness E of the skin 20 is between 0.4 mm and 0.6 mm. mm, preferably equal to 0.5 mm.
• the skin 20 is made of synthetic rubber, for example rubber based on polychloroprene.
• the housing 16 has a first internal cavity 24 for receiving the accelerometer 14 and a second internal cavity 25.
• the first internal cavity 24 is located behind the skin 20.
• the second cavity 25 is disposed behind the first cavity 24.
• the skin 20 is able to guarantee the tightness of the cavities 24, 25.
• the first cavity 24 has dimensions substantially identical to those of the accelerometer 14, so that the accelerometer 14 is immobilized in the housing 16.
• the accelerometer 14 is an accelerometer with an axis oriented substantially in a direction normal to the skin 20, to allow a restoration of the vibratory wave transmitted by bone conduction that is homogeneous depending on the different users.
• the mass 22 of protection is made of an absorbent material and suitable for attenuating the vibrations in the high frequencies, especially for frequencies greater than 1000 hertz.
• the mass 22 has a mass substantially equal to 10 grams.
• the sealing skin and the protective mass 22 isolate the accelerometer 14 from noise and climatic disturbances of the external environment.
• the connecting arms 18 form acoustic decoupling means between the microphone 4 and the module 6 to which the microphone 4 is connected.
• the two arms 18 are interconnected by a thin connecting wall 26, visible in FIGS. 2 and 3.
• the connecting wall 26 is integral with each of the two arms 18.
• Each arm 18 has a first outer edge 28 facing the first outer edge 28 of the other arm 18, and a second outer edge 29 diametrically opposite its first outer edge 28.
• the connecting wall 26 is disposed between the first outer edges 28 and facing one of the other, two connecting arms 18.
• the spacing between the first outer edges 28, represented by the distance D1 in FIG. 3 and the distance D2 in FIG. 4, is gradually increasing from the microphone 4 towards the corresponding acoustic module 6.
• the distance D1 is in particular less than the distance D2.
• the progressively increasing separation, from the microphone 4 to the acoustic module 6, between the first outer edges 28 opposite one another of the two connecting arms 18, is adapted to allow attenuation of sound mechanical waves propagating from the microphone 4 to the corresponding acoustic module 6.
• the distance D3 is in particular less than the distance D4.
• the progressively increasing separation, from the microphone 4 to the acoustic module 6, between the second outer edges 29 of the two connecting arms is adapted to allow attenuation of mechanical sound waves propagating from the microphone 4 to the corresponding acoustic module 6.
• Each connecting arm 18 has an inner opening 30 extending substantially vertically in the direction of the connecting arm 18 and a rib 32 projecting away from the skin 20, as shown in FIGS. 3 and 6. communicates with the second cavity 25.
• Each acoustic module 6, visible in Figure 1 comprises a support plate 34 on a lateral side of the skull and a transducer 36 of mechanical bone excitation.
• a hinge 38 is provided between the support plate 34 and the transducer
• Each plate 34 comprises a support plate 40 able to bear on the skull above an ear. A clearance passage of the ear is formed in the lower part of each plate 40.
• Each plate 34 has, in the rear part of the plate 40, a housing 42 formed of two half-shells 44, 46, fixed together by means 48.
• the support plate 40 and the two half-shells 44, 46 of the housing 42 are, for example, plastic and injection molded.
• the bone mechanical excitation transducer 36 of each acoustic module 6 comprises an emissive element, not shown, and two half-shells 50, 52 protecting the emissive element.
• the emissive element is able to transform an electrical signal received into vibratory waves representative of the sound signal and to transmit them to the auditory nerve by bone conduction.
• the half-shells 50, 52 are, for example, plastic and injection molded.
• a cable 54, visible in FIG. 6, connecting the accelerometer 14 and the corresponding housing 42 is fixed in one of the two orifices 30 by fixing means 56, such as adhesive means.
• a user of the acoustic device 2 begins by positioning the device 2 on his head, by placing the strap 8 on the top of his skull, the rear arch 10 behind his head, near his neck and the support plates 34 on the lateral flanks of his skull, above each respective ear.
• the clearance formed in the lower part of the support plates 40 ensures good ergonomics of the plate 34 relative to the upper part of the flag of the ear.
• the user After positioning the device 2 on his head, the user adjusts the upper arch 8 on his head and the rear arch 10 on his neck.
• the adjustment of the microphone 4 on the skin of the cheek and the mandibular bone takes place naturally and automatically through the corresponding articulation 38 and the flexibility of the connecting arms 18.
• the adjustment of the position of each bone mechanical excitation transducer 36 on the corresponding temple takes place naturally and automatically by each articulation 38.
• the mechanical impedance of the skin 20 of the microphone housing is substantially equal to the mechanical impedance of the user's cheek, the reception by the accelerometer 14 of mechanical vibratory waves of the sound signal coming from the vocal chords is much better.
• the mounting of the accelerometer is by the skin 20 equivalent to a mounting where the accelerometer would be directly disposed in contact with the cheek of the user who would be slightly thicker. The disturbances in reception due to the material of the housing 16 are therefore significantly reduced.
• the acoustic device 2 also allows a high attenuation of vibrations at high frequencies, by the immobilization of the accelerometer 14 in the housing 16 and the mass 22 protection.
• the immobilization of the accelerometer 14 and the inertia of the mass 22 indeed allow good damping parasitic mechanical movements, due in particular to airborne noise.
• the acoustic device 2 thus allows a good reception by bone conduction of the movements of mechanical vibratory waves of the sound signal from the vocal cords, while significantly reducing the mechanical disturbances due to parasitic airborne noise.
• the acoustic decoupling means between the microphone 4 and the module 6 make it possible to limit a mechanical disturbance of the microphone 4 by the acoustic module 6, when the sound signal is received.
• the decoupling means also allow, by the flared form of the spacing between the connecting arms 18 and the microphone 4 to the acoustic module 6, a significant attenuation of the mechanical vibratory waves propagating from the microphone 4 in the direction
• the acoustic decoupling means therefore strongly limit the mutual disturbances between the microphone 4 and the corresponding acoustic module 6.
• the acoustic device 2 according to the invention thus makes it possible to obtain a good reception of the sound signal coming from the vocal cords and a good transmission of vibratory waves to the auditory nerve by bone conduction.
• the upper bow 8 allows, because of its small thickness and its flexible material, wearing a heavy helmet without discomfort on the top of the head.
• the mechanical support of the microphone 4 and the two modules 6 is provided by the rear arch 10, while the upper arch 8 has a role of holding in position on the top of the head.
• the transducer of the contact microphone is enclosed in a rubber protective casing, the protective casing being itself fixed in the first internal cavity of the housing of the contact microphone.
• the support wall is integral with the protective envelope.
• the acoustic device 2 does not include an acoustic module.
• the acoustic device 2 is suitable for use with a biker helmet, a helmet for a motor vehicle driver, a helmet for an armored vehicle, a fireman's helmet, a helmet for a safety officer, a helmet construction helmet, a helmet for an aircraft pilot.
• the acoustic device 2 is a headphone for a switchboard operator.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Details Of Audible-Bandwidth Transducers (AREA)

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• 2009
  • 2009-05-20 FR FR0953398A patent/FR2945905B1/fr not_active Expired - Fee Related
• 2010
  • 2010-05-19 EP EP10728788.0A patent/EP2433431B1/de active Active
  • 2010-05-19 WO PCT/FR2010/050969 patent/WO2010133807A1/fr not_active Ceased
  • 2010-05-19 ES ES10728788T patent/ES2704450T3/es active Active

Non-Patent Citations (1)

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