Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Matshushita Electric Industrial Co., Ltd.

Ushio Sangawa

Hiroshi Kanno

Kazuyuki Sakiyama

Tomoyasu Fujishima

Masahiko Hashimoto

Yuriko Kaneko

Takuya Iwamoto

Kazuaki Takahashi

Norihisa Mino

Suguru Fujita

Masaki Yamamoto

Kenichi Maeda

Shinkichi Ikeda

Kazuo Yokoyama

Keishi Kubo

Hiroyuki Takeuchi

Shinichiro Ueno

Takeo Satoh

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.

Optical microphone

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.

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/m; 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.

Porous silica material and optical microphone

A porous silica material in which silica particles are connected to one another three-dimensionally, wherein: the porous silica material includes a through hole including first pores smaller than a mean free path of an air, and second pores larger than the first pores; the porous silica material has a density of 100 kg/mor more and 300 kg/mor less; and an isobutyl group is bound to silicon of silica of the silica particles.

Porous silica material and optical microphone using the same

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.

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. 0-order, +1-order and &#x2212;1-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 +1-order or &#x2212;1-order diffracted light wave of the outward path and the &#x2212;1-order or +1-order diffracted light wave of the return path.

There is provided an optical microphone for detecting an acoustic wave propagating in an ambient fluid, the optical microphone including: a propagation medium section; a light source for emitting a light wave to be transmitted through a diffraction region in the propagation medium section; and a photoelectric conversion section for detecting the light wave having been transmitted through the propagation medium section. A first acoustic wave which is a portion of the acoustic wave and a second acoustic wave which is another portion thereof are allowed to propagate in the propagation medium section so as to simultaneously arrive at the diffraction region, and an interference component between a +1order diffracted light wave and a &#x2212;1order diffracted light wave of the light wave generated based on a refractive index distribution of the propagation medium occurring in the diffraction region.

A method of producing a porous silica material includes: preparing a raw material solution containing silicon alkoxides including diisobutyldimethoxysilane and tetramethoxysilane in such a mass ratio that a mass of the diisobutyldimethoxysilane is 0.25 or more and 1 or less per mass of the tetramethoxysilane, and a solvent; obtaining a wet gel by adding, to the raw material solution, an aqueous solution containing a catalyst for promoting hydrolysis and condensation polymerization of the silicon alkoxides, the aqueous solution having a pH of 8.9 or more and 11.3 or less; washing the wet gel; and drying the washed wet gel under supercritical conditions.

Method for producing porous silica material

An optoacoustic convolver includes: a light source; a first acoustic waveguide filled with a light-transmissive first acoustic medium; a second acoustic waveguide filled with a light-transmissive second acoustic medium; an optical system whereby light emitted from the light source is split into a first light beam and a second light beam, the first light beam entering the first acoustic waveguide, and the second light beam entering the second acoustic waveguide, thereby generating interference light between the first light beam having passed through the first acoustic waveguide and the second light beam having passed through the second acoustic waveguide; a light-receiving section for receiving the interference light and outputting an electric signal based on an intensity of the received light; and a correlation determination section for determining whether the received signal is correlated with the reference signal by observing the electric signal output from the light-receiving section.

Optoacoustic convolver

A photonic crystal device according to the present invention includes: a first dielectric substratehaving a first lattice structure, of which the dielectric constant changes periodically within a first plane; a second dielectric substratehaving a second lattice structure, of which the dielectric constant changes periodically within a second plane; and an adjustment device (pivot) for changing a photonic band structure, defined by the first and second lattice structures, by varying relative arrangement of the first and second lattice structures. The first and second dielectric substratesandare stacked one upon the other.

Photonic crystal device

The connection topology of input terminals, elementsandand loadis designed similarly to a so-called 'seven-segment display', which is often used to display numerals on an electronic calculator or a digital watch. More specifically, suppose in the three horizontally running segments, the top and bottom segments are associated with the input terminalsand the loadis allocated to one of the four vertically running segments. Then, the three other vertical segments and the other horizontal segment are associated with the elementsand, which are an inductor with an inductance of 5.119 nH, a capacitor with a capacitance of 1.370 pF, an inductor with an inductance of 8.360 nH and a capacitor with a capacitance of 5.942 pF, respectively. By adopting this circuit configuration, the total number of elements can be reduced to four and the lossc can be reduced significantly. In addition, since the resonant circuits can be eliminated and the size of the ladder circuit can be reduced, impedance matching is achieved with a high degree of stability.

Dual-frequency matching circuit

The connection topology of input terminals (), elements (and) and load () is designed similarly to a 'seven-segment display' that is often used to display numerals on a calculator or a digital watch. Specifically, suppose in the three horizontally running segments of the seven-segment display, the top and bottom ones are associated with the input terminals () and the load () is allocated to the other horizontal one. Then, the other four vertical segments are associated with the elements (and), which may be an inductor with an inductance of 4.030 nH, an inductor with an inductance of 11.208 nH, an inductor with an inductance of 2.497 nH, and a capacitor with a capacitance of 2.233 pF, respectively. By adopting this circuit configuration, the total number of elements can be reduced to four and the loss can be reduced significantly. Since the resonant circuits can be eliminated and the size of the ladder circuit can be reduced, impedance matching is achieved with a high degree of stability in spite of a variation in the impedance of the load ().

The connection topology of input terminals (), elements (and) and load () is designed similarly to a 'seven-segment display' that is often used to display numerals on a calculator or a digital watch. Specifically, suppose in the three horizontally running segments of the seven-segment display, the top and bottom ones are associated with the input terminals () and the load () is allocated to the other horizontal one. Then, the other four vertical segments are associated with the elements (and), which may be an inductor with an inductance of 2.132 nH, an inductor with an inductance of 8.266 nH, an inductor with an inductance of 0.596 nH, and a capacitor with a capacitance of 2.097 pF, respectively. By adopting this circuit configuration, the total number of elements can be reduced to four and the loss can be reduced significantly. Since the resonant circuits can be eliminated and the size of the ladder circuit can be reduced, impedance matching is achieved with a high degree of stability in spite of a variation in the impedance of the load ().

The connection topology of input terminals (), elements (and) and load () is designed similarly to a 'seven-segment display' that is often used to display numerals on a calculator or a digital watch. Specifically, suppose in the three horizontally running segments of the seven-segment display, the top and bottom ones are associated with the input terminals () and the load () is allocated to the other horizontal one. Then, the other four vertical segments are associated with the elements (and), which may be an inductor with an inductance of 2.521 nH, an inductor with an inductance of 76.157 nH, an inductor with an inductance of 1.907 nH, and a capacitor with a capacitance of 1.429 pF, respectively. By adopting this circuit configuration, the total number of elements can be reduced to four and the loss can be reduced significantly. Since the resonant circuits can be eliminated and the size of the ladder circuit can be reduced, impedance matching is achieved with a high degree of stability in spite of a variation in the impedance of the load ().

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Nara, Japan

Ushio Sangawa