Abstract: The Invention refers to an airborne ultrasound testing system for a test object (3) containing an ultrasound generator (1; 9) and an ultrasound receiver (2) and a control to control both and a computer assisted test result interface to display an image of the tested test object (3). The ultrasound generator (1) is a resonance-free thermo-acoustic ultrasound generator which does not rely on mechanically deformable or oscillating parts and the ultrasound receiver (2) is a membrane-free and resonance-free optical microphone in an air or gas coupled pulse echo arrangement or in an air or gas coupled transmission mode arrangement. With this testing system, it is possible to test objects with high precision and without liquids and disturbing ringing effects.

Abstract: A wireless location-based gas detection system and method includes a gas detector for wirelessly detecting location information associated with a hazardous gas event. The gas detector includes one or more remote gas sensors that monitor for the occurrence of a gas event and wirelessly communicates information with respect to the location of the event in association with time information to a server or location manager. A wireless communication device in association with one or more location anchor points periodically and under event conditions, transmits the location information and the gas concentration level. A location engine calculates an estimated location of the gas detector based on information received from the wireless communication device and provides the location data to the location manager. The location manager records the gas concentration level, the estimated location, and the time information and stores this information within a database.

Abstract: An LED lamp acquires its location information from the outside through its power-line communication section and stores the acquired location information in nonvolatile storage device. A communication control section, which establishes visible light communication, uses visible light to transmit, at a predetermined timing, the location information read from a location information storage area in the nonvolatile storage device.

Abstract: A system for detection of speech related acoustic signals by using laser based detection that includes a mask configured for being worn over a face part of a speaker covering the speaker's mouth, where the mask includes at least one reflective coating covering at least one area of the mask that reflects collimated electromagnetic signals; and a laser microphone configured for detecting vibrations of the reflective coating area for detection of acoustic signals associated with speech of the speaker by using collimated electromagnetic signals. The mask the reflective coating area thereof allow enhancing detection of vibrations resulting from speech carried out by the speaker wearing said mask.

Abstract: An optical microphone includes: a light source; a first polarizer for allowing linearly-polarized light, of light output from the light source, to pass therethrough; a second polarizer for allowing linearly-polarized light having a different polarization plane from the first polarizer to pass therethrough; a sound-receiving section including an acoustic medium having a smaller sound velocity than the air, wherein an acoustic signal propagates through the acoustic medium, the sound-receiving section being arranged so that the linearly-polarized light from the first polarizer passes through the acoustic medium and enters the second polarizer; and a photodetector for converting an intensity of light having passed through the second polarizer to an electric signal, wherein between the first polarizer and the second polarizer, the linearly-polarized light having passed through the first polarizer is given different phase shifts in two orthogonal directions which are each different from a polarization direction.

Abstract: An optical microphone includes: a propagation medium portion; a light source to output a light wave passing through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a reflecting section to retroreflect the light wave having passed through the propagation medium portion; and a photoelectric conversion section to receive the light wave having been reflected by the reflecting section and passed through the propagation medium portion to output an electric signal. 0th-order, +1st-order and ?1st-order diffracted light waves are respectively produced on outward and return paths, by virtue of a refractive index distribution across the propagation medium portion caused by the propagation of the acoustic wave therethrough. The photoelectric conversion section detects interference light between the +1st-order or ?1st-order diffracted light wave of the outward path and the ?1st-order or +1st-order diffracted light wave of the return path.

Abstract: A device (100) for converting an acoustic signal (102) into an electric signal (104), wherein the device (100) includes an interferometer (106) including two mirrors (108) adapted for reflecting electromagnetic radiation (112) coupled into a space (110) between the mirrors (108). The acoustic signal (102) is to be coupled into the space (110) for influencing the electromagnetic radiation (112) in accordance with this acoustic signal. An electromagnetic radiation detector (112) is adapted for detecting the influenced electromagnetic radiation (112) and for converting the detected influenced electromagnetic radiation (112) into the electric signal (104) being indicative for the acoustic signal (102). An operation point stabilization unit stabilizes an operation point of the device (100).

Abstract: A system for detection of speech related acoustic signals by using laser based detection that includes a mask configured for being worn over a face part of a speaker covering the speaker's mouth, where the mask includes at least one reflective coating covering at least one area of the mask that reflects collimated electromagnetic signals; and a laser microphone configured for detecting vibrations of the reflective coating area for detection of acoustic signals associated with speech of the speaker by using collimated electromagnetic signals. The mask the reflective coating area thereof allow enhancing detection of vibrations resulting from speech carried out by the speaker wearing said mask.

Abstract: A porous silica material disclosed in the present application is a porous silica material in which a plurality of silica particles are connected to one another three-dimensionally, wherein: a density of the porous silica material is less than 220 kg/m3; a particle diameter of the silica particles is 3.5 nm or more; and the water content of the porous silica material is 8 wt % or less.

Abstract: An optical microphone for detecting an acoustic wave propagating through an environmental fluid by using a light wave, includes: an acoustic wave receiving section having a propagation medium portion through which an acoustic wave propagate and a first support portion for supporting the propagation medium portion; a light source for outputting a light wave so that the light wave passes through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a light-blocking portion having an edge line for splitting the light wave having passed through the propagation medium portion into a blocked portion and a non-blocked portion; and a photoelectric conversion section for receiving a portion of the light wave having passed through the propagation medium portion which has not been blocked by the light-blocking portion to output an electric signal.

Abstract: Some embodiments are directed to a photoacoustic sensor. The photoacoustic sensor may comprise: a gas cell with an opening; a light source to generate to radiate a sample gas within the gas cell; an optical microphone to detect the sample gas within the gas cell; and a membrane aligned with the opening of the gas cell to permit sample gas to enter the gas cell. The optical microphone includes a semiconducting laser. The semiconducting laser includes a p-n junction within a cavity of the semiconducting laser. The optical microphone further includes a pressure-sensitive membrane that receives coherent light emitted from the semiconducting laser and directs reflected light back toward the semiconducting laser. During operation of the optical microphone, the pressure-sensitive membrane flexes in response to acoustic pressure waves. The phase of the reflected light is dependent upon a distance of the pressure-sensitive membrane from an aperture of the semiconducting laser.

Abstract: An optical microphone includes: an acousto-optic medium section having a pair of principal surfaces and at least one lateral surface provided therebetween; a restraint section which is in contact with the at least one lateral surface for preventing a shape change of the acousto-optic medium section; and a light emitting section for emitting a light wave so as to propagate through the acousto-optic medium section between the pair of principal surfaces. The pair of principal surfaces are in contact with an environmental fluid through which an acoustic wave to be detected is propagating and are capable of freely vibrating, and an optical path length variation of a light wave propagating through the acousto-optic medium section, which is caused by the acoustic wave that comes into the acousto-optic medium section from at least one of the pair of principal surfaces and propagates through the acousto-optic medium section, is detected.

Abstract: An optical microphone includes: a light source; a first polarizer for allowing linearly-polarized light, of light output from the light source, to pass therethrough; a second polarizer for allowing linearly-polarized light having a different polarization plane from the first polarizer to pass therethrough; a sound-receiving section including an acoustic medium having a smaller sound velocity than the air, wherein an acoustic signal propagates through the acoustic medium, the sound-receiving section being arranged so that the linearly-polarized light from the first polarizer passes through the acoustic medium and enters the second polarizer; and a photodetector for converting an intensity of light having passed through the second polarizer to an electric signal, wherein between the first polarizer and the second polarizer, the linearly-polarized light having passed through the first polarizer is given different phase shifts in two orthogonal directions which are each different from a polarization direction.

Abstract: An arrangement of gravity modulator and gravity-modulation receiver where photons or electromagnetic radiation is modulated electronically or mechanically to reach either a solid, liquid or mixed target possibly through or followed by a surrounding medium to produce gravity modulation in the target to effect gravity signaling which is received by a gravity-modulation receiver in or not in physical contact with the target. In the receiver, one or more piezo-electric transducer/s or quartz crystal/s receive the gravity modulation amplified for further signal processing. When not in physical contact with the target, the piezo-electric transducer/s is/are loaded with a resonator mass of natural resonant frequency either equal to, half, one third or one fifth of the frequency of the gravity modulator, the quartz crystal/s is/are gravity biased with a high-density metal piece along one direction of the oscillation mode of the crystal/s with natural resonant frequency similar to the resonator mass.

Abstract: Method for performing signal processing for an optical microphone. First and second signals corresponding to at least two beams may be generated or received. The first and second signals may be complementary, and may be based on signals provided by one or more photo detectors that receive the at least two beams after the beams return from a sensing structure. The first signal and the second signal may be subtracted to produce a third signal. A position of the sensing structure may be adjusted to cause the third signal to reach a first value, where the adjusting may be performed based on the third signal, and an audio output signal may be provided based on the third signal.

Abstract: An optical microphone includes: a propagation medium portion; a light source to output a light wave passing through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a reflecting section to retroreflect the light wave having passed through the propagation medium portion; and a photoelectric conversion section to receive the light wave having been reflected by the reflecting section and passed through the propagation medium portion to output an electric signal. 0th-order, +1st-order and ?1st-order diffracted light waves are respectively produced on outward and return paths, by virtue of a refractive index distribution across the propagation medium portion caused by the propagation of the acoustic wave therethrough. The photoelectric conversion section detects interference light between the +1st-order or ?1st-order diffracted light wave of the outward path and the ?1st-order or +1st-order diffracted light wave of the return path.

Abstract: Noise may be received through a microphone included in a lighting apparatus. The noise may then be analyzed to determine if a human being may have been the source of the noise, and a message sent over a network alerting other devices that a human-caused noise was detected.

Abstract: Some embodiments relate to an optical microphone according to an example embodiment. The optical microphone includes a semiconducting laser. The semiconducting laser includes a p-n junction within a cavity. The optical microphone further includes an acoustic membrane that receives coherent light emitted from the semiconducting laser and directs reflected light back toward the semiconducting laser. During operation of the optical microphone, the acoustic membrane flexes in response to pressure waves. The phase of the reflected light is dependent upon a distance of the acoustic membrane from the semiconducting laser.

Abstract: An electronic apparatus is provided and includes a light transmitting module configured to convert an electric signal into an optical signal and emit light, a light receiving module configured to receive the light emitted from the light transmitting module and convert the optical signal into an electric signal, and a mover unit configured to cause at least one of the light transmitting module and the light receiving module to carry out linear movement along an optical axis of the light emitted from the light transmitting module and/or rotation about the optical axis.

Abstract: An optical ultrasonic microphone includes an acoustic waveguide that transmits a sound wave received from an opening, an optical acoustic propagation medium that forms at least one portion of a wall face of the acoustic waveguide and an LDV head, and a sound wave proceeding through the acoustic waveguide is received by the optical acoustic propagation medium so that a change in the refractive index caused by the proceeding sound wave inside the optical acoustic propagation medium is generated with high efficiency, and by detecting this as an optical modulation by the LDV head, the optical ultrasonic microphone is allowed to have a very wide band.

Abstract: An acoustoelectric transducer comprising a laser source A and a light receiver H, wherein a soundfield S is provided by which the propagation velocity of the laser beam may be modulated according to the sound pressure while it traverses the soundfield S.

Abstract: Provided is a hearing aid system using a wireless optical communications method. The hearing aid system includes: a voice transmitter that converts addresser's voice into an optical signal to then transmit the converted optical signal; and a hearing aid that restores the optical signal received from the voice transmitter into the addresser's voice to then output the restored addresser's voice. Accordingly, the addresser's voice can directly be transmitted to the hard-of-hearing via wireless optical communications, to thereby prevent a voice discriminating power from lowering even in the case that ambient noise of an addresser as well as a listener is big.

Abstract: A thermoacoustic device includes a sound wave generator and an infra-red reflecting element having an infrared reflection coefficient higher than 30 percent. The infra-red reflecting element can be disposed at one side of the sound wave generator to reflect the emitted heat of the sound wave generator.

Abstract: A light-based skin contact detector is described, including a boot having an index of refraction less than or equal to another index of refraction associated with skin at a frequency of light, a light emitter and detector coupled to the boot and configured to measure an amount of light energy reflected by an interface of the boot, and a digital signal processor configured to detect a change in the amount of light energy reflected by the interface. Embodiments relate to methods for detecting skin contact by measuring an amount of energy reflected by an interface when a boot is not in contact with skin, measuring another amount of energy reflected by another interface when the boot is in contact with the skin, and detecting a change between the amount of energy and the another amount of energy using a digital signal processor.

Abstract: An acoustic system includes a sound-electro converting device, a electro-wave converting device, and a sound wave generator. The electro-wave converting device is connected to the sound-electro converting device. The sound wave generator is spaced from the electro-wave converting device and includes a carbon nanotube structure. The sound-electro converting device converts a sound pressure to an electrical signal and transmits the electrical signal to the electro-wave converting device. The electro-wave converting device emits an electromagnetic signal corresponding to the electrical signal and transmits the electromagnetic signal to the carbon nanotube structure. The carbon nanotube structure converts the electromagnetic signal into heat, and the heat transfers to a medium causing a thermoacoustic effect.

Abstract: A sound wave generator includes a carbon nanotube film. The carbon nanotube film comprises a plurality of carbon nanotubes entangled with each other. At least part of the carbon nanotube film is supported by a supporting element. The carbon nanotube film produces sound by means of the thermoacoustic effect.

Abstract: An apparatus includes a signal device, a power amplifier, and a sound wave generator. The power amplifier is electrically connected to the signal device. The power amplifier outputs an amplified electrical signal to the sound wave generator. The sound wave generator produces sound waves by a thermoacoustic effect. The amplified electrical signal is positive or negative.

Abstract: An optical microphone that may include a first substrate with one or more acoustic entry ports and a die over the one or more acoustic entry ports. The die may include a sensing structure for detecting acoustic vibrations received via the acoustic entry port(s) and may form a first cavity between the first substrate and the sensing structure. The microphone may include a light source within the first cavity, which may transmit laser light. The optical microphone may include photo detector(s) within the first cavity. The one or more photodetectors may be configured to receive the laser light after reflection from the sensing diaphragm to measure the acoustic vibrations of the sensing diaphragm. The microphone may also include a circuit and a lid, where the die, light source, photo detectors, and circuit are comprised within the cavity of the microphone. The circuit may perform signal processing signals from the photodetector(s).

Abstract: A transfer circuit that transmits a signal includes an electrical signal sending section that sends a sending signal, a current to light converting section that converts the sending signal to an optical signal, an optical signal transmitting section that transmits the optical signal, a photo-electric converting circuit that converts the optical signal to an electrical signal, and an electrical signal receiving section that detects a data value of the electrical signal. The photo-electric converting circuit includes a level measuring section that compares the intensity of the electrical signal and a predetermined reference level to detect a data value of the electrical signal, and a measurement controlling section that controls the reference level. The electrical signal receiving section includes a receiving circuit that detects a data value of the electrical signal, and a timing controlling section that controls latch timing at which the receiving circuit detects the data value.

Abstract: An acoustoelectric transducer comprising a laser source A and a light receiver H, wherein a soundfield S is provided by which the propagation velocity of the laser beam may be modulated according to the sound pressure while it traverses the soundfield S.

Abstract: An optical acoustoelectric transducer having a directivity pattern like a better 8 by receiving by a light-receiving element a reflected fraction of the light from a light-emitting device disposed at the center of a bottom plate that is parallel to a diaphragm, has an opening through which an acoustic wave enters, and is connected to supporting side plates. An optical acoustoelectric transducer having uniform amplitude characteristics in a wide frequency range by mixing by a mixer circuit the outputs of a plurality of optical microphones having diaphragms of mutually different thicknesses so as to make the receiving sensitivity uniform in different frequency ranges. A directional optical acoustoelectric transducer having a small size and wide band characteristics by arranging a plurality of light-emitting devices (LD) and a plurality of light-receiving elements (PD) corresponding to a plurality of diaphragms arranged parallel.

Abstract: A method, apparatus, and system for optical communications. An optical transmit signal is generated in response to an electrical transmit signal. The optical transmit signal is coupled into a single communication link for transmission there over. An optical receive signal is received from the single communication link, and in response an electrical receive signal is generated.

Abstract: A fine displacement detection device by sound or the like: which can easily align individual optical components; which disposes a light emitting element (13) and a light receiving element (14) on a substrate, emits light from the light emitting element (13) to a diaphragm (I) set at a position facing the substrate, receives light reflected from the diaphragm (1) by the light receiving element (14), and detects as an electric signal the fine displacement of the diaphragm (1) by sound or the like; and which provides, on the optical paths of the substrate and the diaphragm (1), a focusing element (2) that focuses an incidence light from the light emitting element (13) for leading to the diaphragm (1) and focuses a diverged/reflected light from the diaphragm (1) for leading to the light receiving element (14), and a reflected light flux dividing element (3) that divides the diverged/reflected light focused by the focusing element (2) for leading to the light receiving element (14).

Abstract: An optical communication system is provided which includes an optical signal transmitter which communicates high bandwidth, high power frequencies. The optical signal transmitter includes a high efficiency/high power optical source such as an optical magnetron or a phased array source of electromagnetic radiation, and a modulator element. The modulator element may be within a resonance cavity of the high efficiency/high power optical source (intra cavity) or external to the cavity (extra cavity). The modulator element serves to modulate output radiation of the high efficiency/high power optical source to produce a modulated high frequency optical signal which may be transmitted through the air. The optical signal transmitter is particularly useful in providing the last mile connection between cable service operators and end users.

Abstract: An optical-acoustic transducer in which light is irradiated to a reflecting portion from a light emitter, and a reflected light from the reflecting portion is received with a light receiver to detect a position of a vibrating section, cantilevers are formed by performing slit working for a diaphragm, portions between an outer circumference edge of the vibrating section and inner circumference edges of the cantilevers and portions between an inner circumference edge of a supporting portion and outer circumference edges of the cantilevers are partitioned by the slit working, and the cantilevers extend along an outer circumference of the vibrating section.

Abstract: An Improved Signal Receiver Having Wide Band Amplification Capability is disclosed. Also disclosed is a receiver that is able to receive and reliably amplify infrared and/or other wireless signals having frequency bandwidths in excess of 40 MHz. The receiver of the present invention reduces the signal-to-noise ratio of the received signal to ?th of the prior systems. The preferred receiver eliminates both the shunting resistor and the feedback resistor on the input end by amplifing the signal in current form. Furthermore, the receiver includes transconductance amplification means for amplifying the current signal without the need for Cascode stages. Finally, the receiver includes staged amplification to amplify the current signal in stages prior to converting the signal into a voltage output.

Abstract: An On-Off control circuit between the IEEE1394a and IEEE1394b compliant physical layer (PHY) output driver circuitry and the glass fiber optical physical medium dependent (PMD) sub-layer within the architecture of the IEEE 1394b standard addresses the stability issue incurred by electronic circuit's inherent noise that interferes with the connection detecting procedure defined by the connection management protocol (CMP) of the IEEE 1394b standard. The circuit includes of a voltage divider to provide a reference voltage of about 50% of the output common mode voltage, a voltage comparator, and a feedback coupled to the positive input of the comparator to eliminate possible oscillation. The negative input of the comparator may be connected to the mid point of TPB termination network and the positive input of the comparator may be connected to the output of the voltage dividing circuit. The output of the comparator may be connected to the transmission enable bar input of the optical transceiver.

Abstract: A microphone is provided with a simple structure by which a lead wire is not required to detect displacement of a vibrated film. The microphone is equipped with a vibrated film 2 to receive sonic waves on either surface and to receive electro-magnetic waves on other surface, a device 4 to receive and transmit the electro-magnetic waves reflected by the vibrated film, a counter to count pulses from the device to receive and transmit electro-magnetic waves, a processing logic 5 to count the pulses output from the counter. Displacement of the vibrated film is converted into electric signals by counting the processing logic the frequency and amplitude of the electro-magnetic waves reflected by the vibrated film 2.