The present invention relates generally to microphones and specifically to graphene-based microphone diaphragms. Microphones typically are acoustic-to-electric transducers or sensors that convert sound into an electrical signal. Microphones typically include a pressure sensitive diaphragm that can convert sound to mechanical motion, which can subsequently be converted to an electrical signal. Microphone varieties are typically categorized by the transducer type that is incorporated therein, for example, condenser, dynamic, ribbon, carbon, piezoelectric, fiber optic, liquid, pressure-gradient, and microelectric-mechanical system (MEMS). In certain microphones, the diaphragm can be positioned between a fixed internal volume of air and the environment, which allows the microphone to respond uniformly to pressure from a plurality of directions. In other microphones, the diaphragm can be at least partially open on both of its sides, which can result in pressure differences between the two sides that gives the microphones directional characteristics.
The descriptions of the various embodiments of the present invention have been presented for purposes of illustration but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Certain terminology may be employed in the following description for convenience rather than for any limiting purpose. For example, the terms “forward” and “rearward,” “front” and “rear,” “right” and “left,” “upper” and “lower,” and “top” and “bottom” designate directions in the drawings to which reference is made, with the terms “inward,” “inner,” “interior,” or “inboard” and “outward,” “outer,” “exterior,” or “outboard” referring, respectively, to directions toward and away from the center of the referenced element, the terms “radial” or “horizontal” and “axial” or “vertical” referring, respectively, to directions or planes which are perpendicular, in the case of radial or horizontal, or parallel, in the case of axial or vertical, to the longitudinal central axis of the referenced element, and the terms “downstream” and “upstream” referring, respectively, to directions in and opposite that of fluid flow. Terminology of similar import other than the words specifically mentioned above likewise is to be considered as being used for purposes of convenience rather than in any limiting sense.
In the figures, elements having an alphanumeric designation may be referenced herein collectively or in the alternative, as will be apparent from context, by the numeric portion of the designation only. Further, the constituent parts of various elements in the figures may be designated with separate reference numerals which shall be understood to refer to that constituent part of the element and not the element as a whole. General references, along with references to spaces, surfaces, dimensions, and extents, may be designated with arrows. Angles may be designated as “included” as measured relative to surfaces or axes of an element and as defining a space bounded internally within such element therebetween, or otherwise without such designation as being measured relative to surfaces or axes of an element and as defining a space bounded externally by or outside of such element therebetween. Generally, the measures of the angles stated are as determined relative to a common axis, which axis may be transposed in the figures for purposes of convenience in projecting the vertex of an angle defined between the axis and a surface which otherwise does not extend to the axis. The term “axis” may refer to a line or to a transverse plane through such line as will be apparent from context.
Microphones typically are acoustic-to-electric transducers or sensors that convert sound into an electrical signal. Microphones typically include a pressure sensitive diaphragm that can convert sound to mechanical motion, which can subsequently be converted to an electrical signal. Microphone varieties are typically categorized by the transducer type that is incorporated therein, for example, condenser, dynamic, ribbon, carbon, piezoelectric, fiber optic, liquid, pressure-gradient, and micro-electro-mechanical-system (MEMS) microphones. In certain microphones, the diaphragm can be positioned between a fixed internal volume of air and the environment, which allows the microphone to respond uniformly to pressure from a plurality of directions. In other microphones, the diaphragm can be positioned in a manner to be at least partially open on both of its sides, which can result in the formation of pressure differences between the two sides of the diaphragm and results in directional detection characteristics.
Embodiments of the present invention seek to provide graphene-based microphone diaphragms. As used herein, the term microphone and sensor are interchangeable and both denote an electrical device that detects acoustic pressure waves. Other embodiments of the present invention seek to provide microphone diaphragms that comprise a graphene-based composition having graphene sheets. Still other embodiments of the present invention seek to provide printed microphone diaphragms. Additional embodiments of the present invention seek to provide microphone diaphragms that are coated with a reflective material or a metal, which includes, but is not limited to, silver, aluminum, lead, gold, platinum, rhodium, copper, magnesium, brass, bronze, titanium, zirconium, nickel, tantalum, tin, and/or an alloy thereof.
Sensor 100 has a detectable frequency range that can be increased or decreased by decreasing or increasing, respectively, the thickness (i.e. cross-section) of at least a portion of reflective diaphragm 130. As the thickness of reflective diaphragm 130 decreases, the quantity of force that is required by pressure wave 140 to distort reflective diaphragm 130 decreases. As the quantity of force with which pressure wave 140 impacts reflective diaphragm 130 decreases, the thickness of at least a portion of reflective diaphragm 130 can be decreased to facilitate the distortion of reflective diaphragm 130 and detection of pressure wave 140. Photo-emitter 110 can be a fiber optic thread having a photo-emitting first end facing reflective diaphragm 130 and a second end in communication with a photo-source, such as component 115. Photo-emitter 110 can be in communication with component 115, which is an electrical device that can transmit generated light via photo-emitter 110. Photo-collectors 120 can be a fiber optic thread having a photo-collecting first end facing reflective diaphragm 130 and a second end in communication with a photo-detector, such as component 125. Photo-collectors 120 can be in communication with component 125, which is an electrical device that can quantify light received via photo-collectors 120.
Although not shown, components 115 and 125 can be a single component. Components 115 and/or 125 can be in communication with a computing device that controls the operation of components 115 and/or 125. Reflective diaphragm 130 can be positioned at least partially within a housing (not shown) in a manner to facilitate the detection of acoustic pressure (i.e. sound), for example, pressure wave 140. Photo-emitter 110 and photo-collectors 120 can be positioned proximate to reflective diaphragm 130 in a manner to maximize any distortion of reflective diaphragm 130 that results from the impact of pressure wave 140. Photo-emitter 110 can be positioned in a manner to be in approximate alignment with the central axis of the housing and/or reflective diaphragm 130. Photo-collectors 120 can be positioned proximate to photo-emitter 110. Photo-collectors 120 can be positioned radially around photo-emitter 110. Photo-collectors 120 can be positioned asymmetrically or symmetrically relative to photo-emitter 110. Although not shown, sensor 100 can comprise one or more copies of photo emitter 110 and/or photo collector 120.
Sensor 100 may have a sensitivity of up to 1100 nm/kPa and/or have an ability to detect acoustic signals having a noise density as low as 60 μPa/√Hz at 10 kHz. The distance of photo-emitter 110 and photo-detectors 120 relative to reflective diaphragm 130 can be the same or different. Reflective diaphragm 130 can be positioned proximate to photo-emitter 110 and/or photo-detectors 120 at a distance of about 50 μm to about 100 μm, about 100 μm to about 150 μm, about 150 μm to about 200 μm, about 200 μm to about 250 μm, about 250 μm to about 300 μm, about 300 μm to about 350 μm, about 350 μm to about 400 μm, about 400 μm to about 450 μm, about 450 μm to about 500 μm, about 500 μm to about 550 μm, about 550 μm to about 600 μm, about 600 μm to about 650 μm, about 650 μm to about 700 μm, about 700 μm to about 750 μm, about 750 μm to about 800 μm, about 800 μm to about 850 μm, about 850 μm to about 900 μm, about 900 μm to about 950 μm, or about 950 μm to about 1000 μm. In other embodiments, sensor 100 can be any microphone that comprises a diaphragm, including, but not limited to, condenser, dynamic, ribbon, carbon, piezoelectric, fiber optic, laser, liquid, or MEMS microphones.
A discussion of a fabrication method is provided below followed by a discussion of applicable methods and materials.
Applicable materials and methods are discussed below, in accordance with an embodiment of the present invention. Layer 210 can comprise a graphene-based composition (“the composition”). The composition can include graphene sheets. The graphene sheets and/or the composition can be formed utilizing the materials and/or methods that are disclosed in European patent application no. EP20120849213 to Redmond et al., European patent application no. EP20120849443 to Redmond et al., PCT publication no. WO2013074710 Al to Redmond et al., U.S. patent application Ser. No. 13/284,841, to Scheffer et al., U.S. patent application Ser. No. 12/848,152 to Scheffer et al., U.S. patent application Ser. No. 12/753,870 to Scheffer et al., U.S. patent application Ser. No. 13/260,372 to Varma et al., and U.S. patent application Ser. No. 13/140,834 to Scheffer et al. (“the references”) (herein incorporated by reference in their entirety). Substrate 200 and/or layer 300 can comprise one or more substrates that are disclosed in the references. Substrate 200 and/or 300 can be formed using one or more methods disclosed in the references. Layers 210 and/or 600 can be formed using a method disclosed in the references.
Reflective diaphragm 130 can be formed in any applicable manner disclosed in the references. For example, layer 210 can be applied to the surface of substrate 200 at a thickness of about 0.5 μm to about 5.0 μm, 0.5 μm to about 0.75 μm, about 0.75 μm to about 1.0 μm, about 1.0 μm to about 1.25 μm, about 1.25 μm to about 1.5 μm, about 1.5 μm to about 1.75 μm, about 1.75 μm to about 2.0 μm, about 2.0 μm to about 2.25 μm, about 2.25 μm to about 2.5 μm, about 2.5 μm to about 2.75 μm, about 2.75 μm to about 3.0 μm, about 3.0 μm to about 3.25 μm, about 3.25 μm to about 3.5 μm, about 3.5 μm to about 3.75 μm, about 3.75 μm to about 4.0 μm, about 4.0 μm to about 4.25 μm, about 4.25 μm to about 4.5 μm, about 4.5 μm to about 4.75 μm, about 4.75 μm to about 5.0 μm, about 5.0 μm to about 10.0 μm, about 10.0 μm to about 15.0 μm, about 15.0 μm to about 20.0 μm, about 20.0 μm to about 25.0 μm, or about 25.0 μm to about 30.0 μm. Applicable thickness values for the composition can include subvalues that are included in the aforementioned thickness ranges.
The applied composition can be cured at about 80° C. to about 85° C., about 85° C. to about 90° C., about 90° C. to about 95° C., about 95° C. to about 100° C., about 100° C. to about 105° C., about 105° C. to about 110° C., about 110° C. to about 115° C., about 115° C. to about 120° C., about 120° C. to about 125° C., about 125° C. to about 130° C., about 130° C. to about 135° C., about 135° C. to about 140° C., about 140° C. to about 145° C., about 145° C. to about 150° C., about 150° C. to about 155° C., about 155° C. to about 160° C., about 160° C. to about 165° C., about 165° C. to about 170° C., about 170° C. to about 175° C., about 175° C. to about 180° C., about 180° C. to about 185° C., about 185° C. to about 190° C., about 190° C. to about 195° C., about 195° C. to about 200° C. Applicable curing temperatures can include subvalues that are included in the aforementioned curing ranges.
The applied composition can be cured for about 0.5 minutes to about 1.0 minutes, about 1.5 minutes to about 2.0 minutes, about 3.0 minutes to about 3.5 minutes, about 3.5 minutes to about 4.0 minutes, about 4.0 minutes to about 4.5 minutes, about4.5 minutes to about 5.0 minutes, about 5.0 minutes to about 5.5 minutes, about 5.5 minutes to about 6.0 minutes, about 6.0 minutes to about 6.5 minutes, about 6.5 minutes to about 7.0 minutes, about 7.0 minutes to about 7.5 minutes, about 7.5 minutes to about 8.0 minutes, about 8.0 minutes to about 8.5 minutes, about8.5 minutes to about 9.0 minutes, about 9.0 minutes to about 9.5 minutes, or about 9.5 minutes to about 10.0 minutes. Applicable curing times can include subvalues that are included in the aforementioned curing time ranges.
Substrate 200 and/or layer 210 can comprise flexible and/or stretchable materials, silicones and other elastomers and other polymeric materials, metals (such as aluminum, copper, steel, stainless steel, and other metals), adhesives, heat-sealable materials (such as cellulose, biaxially oriented polypropylene (BOPP), poly(lactic acid), polyurethanes), fabrics (including cloths) and textiles (such as cotton, wool, polyesters, rayon), clothing, glasses and other minerals, ceramics, silicon surfaces, wood, paper, cardboard, paperboard, cellulose-based materials, glassine, labels, silicon and other semiconductors, laminates, corrugated materials, concrete, bricks, and other building materials. Substrates can in the form of films, papers, wafers, and/or larger three-dimensional objects.
Substrate 200 can comprise materials that are treated with coatings (such as paints) or similar materials before the layer 210 is applied. Coatings can include indium tin oxide, antimony tin oxide, and similar compositions.
One or more surfaces of layers 210 and/or 300 can be coated with a reflective material. The reflective material may comprise a metal. Applicable metals include, but are not limited to, silver, aluminum, lead, gold, platinum, rhodium, copper, magnesium, brass, bronze, titanium, zirconium, nickel, tantalum, tin, nickel, tin, steel, and/or colloidal metals. The reflective material can be applied to at least a portion of the one or more internally-facing (i.e. towards the photo-emitter) surfaces utilizing any of the aforementioned deposition methods. Alternatively, the reflective material is applied to at least a portion of the internally-facing surface of the diaphragm in a manner sufficient to reflect light to the photo-collector. The reflective material can be deposited using and applicable deposition method, which includes, but is not limited to, spattering, spraying, plating, syringe deposition, spray coating, electrospray deposition, ink-jet printing, spin coating, thermal transfer (including laser transfer) methods, screen printing, rotary screen printing, gravure printing, capillary printing, offset printing, electrohydrodynamic (EHD) printing, flexographic printing, pad printing, stamping, xerography, microcontact printing, dip pen nanolithography, laser printing, via pen or similar means.
In certain embodiments, substrate 200 is a water soluble substrate, such as a water soluble polymer. Applicable water soluble polymers include, but are not limited to, alkaline hydrosoluble copolymers of isobutylene and maleic anhydride, ISOBAM™ (developed by Kuraray Co, LTD), BIOCARE™ polymers (developed by DOW Chemicals), CELLOSIZE™ hydroxyethylcellulose (HEC) (developed by DOW Chemical), DOW™ latex powders (DLP) (developed by DOW Chemical), ETHOCEL™ ethylcellulose polymers (developed by DOW Chemical), KYTAMER™ PC polymers (developed by DOW Chemical), METHOCEL™ water soluble resins (developed by DOW Chemical), POLYOX™ water soluble resins, SoftCAT™ polymers (developed by DOW Chemical), UCARE™ polymers (developed by DOW Chemical), Sokalan® (developed by BASF), Tamol® (developed by BASF), polyacrylamides, polyacrylates, acrylamide-dimethylaminoethyl acrylate copolymers, polyamines, polyethyleneimines, polyamidoamines, polyethylene oxide, rice paper, water soluble paper, ASW-60 (developed by Aquasol Corp.), ASW-35 (developed by Aquasol Corp.), ASW-15 (developed by Aquasol Corp.), ASW-40 (developed by Aquasol Corp.), Dissolov Tech PS (developed by DayMark Technologies), and DissolovTeck 35C (developed by DayMark Technologies), and Ambergum™ water-soluble polymers.
Substrate 200 can be coated with UV-curable water soluble products. Applicable UV-curable water soluble products includes, but is not limited to, Chromafil™ (developed by Chromaline®), CCI Red-Coat (developed by Chemical Consultants, Inc.), isopropanol, Blue Screen Filler No. 60 (developed by Ulano Corp.), Green Extra Heavy Blockout No. 10 (developed by Ulano Corp.), Red Coat Blockout (developed by Lawson Screen Products, Inc.), and Ryo Screen Blockout (developed by Ryonet Corp.).
This application claims priority to U.S. Provisional Application No. 62/140,496 filed Mar. 31, 2015, which is hereby incorporated herein by reference.
Number | Date | Country | |
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62140496 | Mar 2015 | US |