Acoustic audio transducer with aerogel diaphragm

• US 5,748,758 A
• Filed: 01/25/1996
• Issued: 05/05/1998
• Est. Priority Date: 01/25/1996
• Status: Expired due to Fees

• Current Assignee: Jeffrey W. Menasco, Lawrence C. Menasco Jr
• Original Assignee: Jeffrey W. Menasco, Lawrence C. Menasco Jr
• Inventors: Menasco, Jeffrey W., Menasco, Lawrence C. Jr.
• Primary Examiner(s): Kuntz, Curtis A.
• Assistant Examiner(s): Barnie, Rexford N.
• Application Number:
  US08/591,723
• Time in Patent Office: 831 Days
• Field of Search: 381/168, 381/169, 381/176, 381/192, 381/203, 381/205, 381/115, 381/117, 181/242, 423/338, 502/233
• US Class Current: 381/176
• CPC Class Codes: H04R 23/00 Transducers other than those covered by groups H04R9/00 - H04R21/00 diaphragms for transducers of the distributed-mode type H04R7/045

Abstract

This invention describes an acoustic transducer, either speaker or microphone, that uses an aerogel diaphragm or an aerogel acoustic interface made of magnetic aerogel or conductive aerogel or both. In the case of a speaker, the aerogel diaphragm is directly driven either by electromagnetic or electrostatic means to reproduce high fidelity sound. In the case of a microphone, the aerogel diaphragm is modulated by acoustic energy, and in turn, the aerogel diaphragm electromagnetically or electrostatically modulates a field detection element resulting in a high fidelity electrical audio signal output.

Claims

1. An acoustic transducer that converts between electrical energy and acoustic energy comprising:

a) an aerogel diaphragm formed from materials selected from the group consisting of aerogels, aerogel composites, magnetically inductive and magnetically permeable aerogels, and magnetically inductive and magnetically permeable aerogel composites, said aerogel diaphragm having at least one surface used as an acoustical interface,

b) a magnetic field created by magnetic sources selected from the group consisting of permanent magnets and electromagnets,

c) at least one electrical conductor embedded within the sum and substance of said aerogel diaphragm and a means for electrical interface to said conductor, said conductor being integral to said sum and substance of said aerogel diaphragm,

d) said magnetic field being placed in close proximity to said electrical conductor embedded within said aerogel diaphragm, and said electrical conductor being configured to provide means for electromagnetic coupling to said magnetic field, thereby enabling interaction between said magnetic field and said aerogel diaphragm in correspondence with physical movement of said aerogel diaphragm.

2. A method of converting an acoustic signal to an electrical signal by an acoustic transducer comprising the steps of:

a) an aerogel diaphragm formed from material selected from the group consisting of aerogel and aerogel composites, and having at least one surface for acoustical interface, is induced to physically modulate in correspondence with an acoustic signal,

b) at least one conductor is embedded substantially within the bulk volume of said aerogel diaphragm, said conductor being integral to said bulk volume of said aerogel diaphragm, providing a direct correspondence of movement between said aerogel diaphragm and said conductor, thereby modulating said embedded conductor in correspondence with said acoustic signal, said conductor also being configured to provide for an electrical field pickup or electrical field sensor or electrical field transducer means to generate an electrical signal in proportion to a change in strength of an electrical field,

c) said embedded conductor within said aerogel diaphragm is placed substantially in the presence of a permanent electrical field selected from the group consisting of magnetic fields and electrostatic fields, said permanent electrical field being held spatially constant in reference to said aerogel diaphragm and said embedded conductor within said aerogel diaphragm,

d) said acoustic signal physically modulates said embedded conductor within said aerogel diaphragm, causing said embedded conductor to spatially change position in reference to said permanent electrical field, thereby creating an apparent change in strength of field within said embedded conductor, said embedded conductor acting as said electrical pickup, thereby registers said change in strength of field as an electrical output signal in direct proportion to said acoustic signal.

3. A method of converting an acoustic signal to an electrical signal by an aerogel diaphragm and transducer in claim 2 wherein:

a) said aerogel diaphragm is fabricated with said embedded conductor in a substantially spiral or coiled pattern,

b) said embedded conductor within said aerogel diaphragm is placed in close proximity to a strong permanent magnet, said permanent magnet emanating an electromagnetic field of predetermined strength,

c) said embedded conductor within said aerogel diaphragm is induced to couple to said electromagnetic field,

d) said aerogel diaphragm being physically modulated by said acoustic signal, thereby modulates said embedded conductor within said aerogel diaphragm, causing said embedded conductor to change position relative to said electromagnetic field in correspondence with said modulation, wherein an electric current is generated within said embedded conductors, said electric current functioning as an electric signal in correspondence with said acoustic signal.

4. An acoustical transducer that converts between electrical energy and acoustic energy comprising:

a) an aerogel acoustical interface or aerogel membrane or aerogel transducer element or aerogel diaphragm, said aerogel diaphragm being formed from electrical field-reactive materials selected from the group consisting of conductive aerogels, conductive aerogel composites, magnetically inductive and magnetically permeable aerogels, and magnetically inductive and magnetically permeable aerogel composites, said aerogel diaphragm having at least one surface used as an acoustical interface,

b) a means for converting between electrical energy and electrical field energy, said electrical field being directly coupled to said field-reactive materials of said aerogel diaphragm, said electrical field having a correspondence with the physical movement of said aerogel diaphragm, and

c) an array of electromagnetic coils in combination with an aerogel diaphragm formed from a magnetically reactive material, said diaphragm being placed in close proximity to said array, disposing said aerogel diaphragm to electromagnetically couple to said array, said aerogel diaphragm having at least one surface for acoustical interface, said array providing means for a plurality of electromagnetic modulation modes, said modulation modes being in correspondence with an electrical audio signal, whereby acoustic energy is produced in correspondence with said electrical audio signal.

6. An acoustic transducer that converts between electrical energy and acoustic energy of claim 4, wherein a complex array modulation mode is used to create a spatial acoustic effect similar to an acoustical portal or audio window, hereafter referred to as an audio window, said complex array modulation mode comprising one mode of said modulation modes, said complex array modulation mode being effected by means where said electromagnetic coils of said array are each configured to be independently electrically modulated, thereby disposing said array to generate a complex electromagnetic field, said field having a complex terrain of electromagnetic field densities substantially corresponding to a cross-sectional complex pressure gradient representing the acoustic content at the intersection of a planar cross-section of a complex acoustic signal, said complex electromagnetic field urging each portion of said aerogel diaphragm to move in correspondence with said field densities of said complex electromagnetic field, thereby projecting a complex acoustic image across said acoustical interface of said aerogel diaphragm, whereby said spatial acoustical effect referred to as said audio window is realized.

7. A method of converting an acoustical signal to an electrical signal comprising the steps of:

a) an aerogel diaphragm formed from electric field-reactive materials selected from the group consisting of conductive aerogels, conductive aerogel composites magnetically inductive and magnetically permeable aerogels, and magnetically inductive and magnetically permeable aerogels composites, and having at least one surface for acoustical interface, is induced to physically modulate by an acoustic signal in correspondence with said acoustic signal,

b) an electrical field selected from a group consisting of electromagnetic fields and electrostatic fields is generated or imparted within said electric field-reactive material of said aerogel diaphragm by an electrical field generating means,

c) an electrical field sensor or pick up transducer capable of generating an electrical output in correspondence with a change in electrical field strength is placed substantially within said electrical field emanating from said aerogel diaphragm, said electrical field sensor being kept at a fixed position in reference to the position of said aerogel diaphragm,

d) said electrical field emanating from said aerogel diaphragm is spatially displaced or modulated in correspondence with the physical modulation of said aerogel diaphragm, the spatial displacement being perceived as a change in strength of said electrical field by the fixed electrical field sensor, whereby an electrical signal is created by said electrical field sensor in correspondence with said acoustic signal,

e) said aerogel diaphragm being formed from conductive materials is effectively configured to be one potential and side of a condenser element or capacitor, with the other potential and side being a fixed conductive element placed in proximity to said aerogel diaphragm, the surface area of fixed conductive element being approximately shaped to correspond to the surface of said acoustical interface of aid aerogel diaphragm, said fixed conductive element also having means for acoustical transparency,

f) said condenser element is configured with a bias voltage applied across the two potentials, one potential being directly connected to one side of said bias voltage, and the other side of said bias voltage being connected through a resistor to the opposite potential of said condenser element, with a relative charge corresponding to the capacitance across said condenser element, said capacitance being relative to the position of said aerogel diaphragm in reference to said fixed conductive element, and

g) said aerogel diaphragm being physically modulated by said acoustic signal in reference to said fixed conductive element, effects a change in capacitance across said condenser element, thereby creating a modulated voltage differential across said resistor in correspondence with said modulated aerogel diaphragm, whereby said voltage differential provides for an electrical audio signal in correspondence with said acoustic signal.

5. An acoustic transducer that converts between electrical energy and acoustic energy of claim 8 wherein said modulation modes is selected from the group consisting of amplitude modulation, Bessel array modulation, and phase array modulation.

8. A method of converting an acoustic signal to an electrical signal by an aerogel diaphragm and transducer of claim 7 wherein:

a) said aerogel diaphragm being formed from magnetic material and made with a permanent magnetic moment, and having an electromagnetic field created by said permanent magnetic moment, and having means of suspension that allows for the physical modulation of said aerogel diaphragm by said acoustic signal, said aerogel diaphragm is placed in close proximity to an electromagnetic sensing means, said sensing means providing for an electric signal as an output in correspondence with a detected change in electromagnetic field strength,

b) said electromagnetic field of said aerogel diaphragm is caused to couple to said electromagnetic sensing means,

c) said acoustic signal physically modulates said aerogel diaphragm, mutually displacing said diaphragm and said electromagnetic field emanating from said diaphragm, thereby effecting a change in the relative field strength of said electromagnetic field as detected by said electromagnetic sensing means,

d) said electromagnetic sensing means produces a modulated electrical signal in correspondence with the detected modulated relative field strength, thereby providing for an electrical signal in correspondence with said acoustic signal.