Abstract: An optical displacement sensor comprises a reflective surface and one or more diffraction gratings which, together with the reflective surface, each define a respective interferometric arrangement. The reflective surface is moveable relative to the diffraction grating(s) or vice versa. Light from a light source propagates via the interferometric arrangement(s) to produce an interference pattern at a respective set of photo detectors. Each interference pattern depends on the separation between the reflective surface and the respective grating. A collimating optical arrangement at least partially collimates the light between the light source and the diffraction grating(s).

Abstract: A field detector (2) comprises a field-responsive element (10) which undergoes a dimensional change when exposed to a predetermined field; and an interferometric read-out arrangement arranged to detect the dimensional change of the field-responsive element. A light source (4) is arranged to provide a measurement beam reflected from the field-responsive element (10) and a reference beam not reflected from the field-responsive element (10), an optical detector (6) being disposed so as to detect at least part of an interference pattern produced by the measurement beam and the reference beam. The field-responsive element (10) has a shape comprising a curved surface and is constrained at least one edge (12) thereof such that the dimensional change causes the curved surface to be displaced in a direction which changes an optical path length of the measurement beam relative to the reference beam, thereby changing the interference pattern detected by said optical detector.

Abstract: An optical microphone assembly including a micro-electromechanical system (MEMS) component, a semiconductor chip, and an outer housing including at least part of a non-MEMS supporting structure and defining an aperture. The MEMS component includes an interferometric arrangement which includes a membrane and at least one optical element spaced from the membrane. The semiconductor chip includes at least one photo detector and a light source. The MEMS component is mounted on the non-MEMS supporting structure and sealed to the outer housing such that the MEMS component closes the aperture. The semiconductor chip is mounted separately from the MEMS component on the non-MEMS supporting structure in a spaced relationship with the MEMS component such that the MEMS component is displaced relative to the semiconductor chip in a direction perpendicular to a reflecting surface of the membrane.

Abstract: An optical microphone assembly comprises a rigid substrate; an interferometric arrangement, a light source, at least one photo detector and an enclosure. The interferometric arrangement comprises a membrane and at least one optical element spaced from the membrane, wherein the at least one optical element comprises a surface of the substrate and/or is disposed on a surface of the substrate. The light source is arranged to provide light to the interferometric arrangement such that a first portion of the light propagates along a first optical path via the interferometric arrangement and a second portion of the light propagates along a second different optical path via the interferometric arrangement, thereby giving rise to an optical path difference between the first and second optical paths which depends on a distance between the membrane and the optical element.

Abstract: An optical microphone assembly comprises a rigid substrate; an interferometric arrangement, a light source, at least one photo detector and an enclosure. The interferometric arrangement comprises a membrane and at least one optical element spaced from the membrane, wherein the at least one optical element comprises a surface of the substrate and/or is disposed on a surface of the substrate. The light source is arranged to provide light to the interferometric arrangement such that a first portion of the light propagates along a first optical path via the interferometric arrangement and a second portion of the light propagates along a second different optical path via the interferometric arrangement, thereby giving rise to an optical path difference between the first and second optical paths which depends on a distance between the membrane and the optical element.

Abstract: A field detector (2) comprises a field-responsive element (10) which undergoes a dimensional change when exposed to a predetermined field; and an interferometric read-out arrangement arranged to detect the dimensional change of the field-responsive element. A light source (4) is arranged to provide a measurement beam reflected from the field-responsive element (10) and a reference beam not reflected from the field-responsive element (10), an optical detector (6) being disposed so as to detect at least part of an interference pattern produced by the measurement beam and the reference beam. The field-responsive element (10) has a shape comprising a curved surface and is constrained at least one edge (12) thereof such that the dimensional change causes the curved surface to be displaced in a direction which changes an optical path length of the measurement beam relative to the reference beam, thereby changing the interference pattern detected by said optical detector.

Abstract: The present invention relates to a displacement sensor device and the system including the device, wherein the device comprises a first at least partially transparent plane surface with a first diffraction pattern and a second plane surface comprising a second reflecting diffraction pattern. The diffractive patterns being adapted to diffract light within a chosen range of wavelengths, the second surface being positioned below and parallel to the first surface constituting a pair wherein said first and second diffractive patterns being essentially equal, the device also comprising displacement means for allowing a movement in a direction parallel to said surfaces, the device thus providing a movement sensitive diffraction pattern.

Abstract: The present invention relates to an optical displacement sensor comprising a first at least partially reflective surface and a second surface having a diffractive pattern, the surfaces being provided on elements having a variable distance between them, each surface pair defining a cavity between them. The sensor also comprising at least one light source transmitting light at least one a chosen wavelength range into said cavities and at least one light detector receiving light from the cavities, wherein said diffractive patterns are adapted to direct light toward at least one detector provided in a known position relative to said diffractive surfaces.

Abstract: The present invention relates to a gas detector cell unit comprising a gas cell, the unit comprising an outer housing providing access to the gas outside through a protecting filter adapted to making gas cell safe for use in explosive environments, i.e. a sintered filter, and the unit comprising means for detecting reduction in the circulation through said protecting filter.

Abstract: The present invention relates to a gas detector cell and cell unit for optical detection of a predetermined gas, the cell being provided with optical means for investigating a gas sample present in the cell. The cell is constituted by a volume enclosed in a container, at least part of the container wall being constituted by a membrane, the membrane being provided with openings allowing diffusion of gas therethrough, and the membrane openings being provided with a catalyst for converting the gas diffusing therethrough to said predetermined gas.

Abstract: An optical microphone arrangement comprises: an array of optical microphones (4) on a substrate (8), each of said optical microphones FIG. 2 (4) providing a signal indicative of displacement of a respective membrane (24) as a result of an incoming audible sound; at first processor (12) arranged to receive said signals from said optical microphones (4) and to perform a first processing step on said signals to produce a first output; and a second processor (14) arranged to receive at least one of said signals or said first output; wherein at least said second processor (14) determines presence of at least one element of human speech from said audible sound.

Abstract: The present invention relates to a displacement sensor device and the system including the device, wherein the device comprises a first at least partially transparent plane surface with a first diffraction pattern and a second plane surface comprising a second reflecting diffraction pattern. The diffractive patterns being adapted to diffract light within a chosen range of wavelengths, the second surface being positioned below and parallel to the first surface constituting a pair wherein said first and second diffractive patterns being essentially equal, the device also comprising displacement means for allowing a movement in a direction parallel to said surfaces, the device thus providing a movement sensitive diffraction pattern.

Abstract: The present invention relates to an optical displacement sensor comprising a first at least partially reflective surface and a second surface having a diffractive pattern, the surfaces being provided on elements having a variable distance between them, each surface pair defining a cavity between them. The sensor also comprising at least one light source transmitting light at least one a chosen wavelength range into said cavities and at least one light detector receiving light from the cavities, wherein said diffractive patterns are adapted to direct light toward at least one detector provided in a known position relative to said diffractive surfaces.

Abstract: The present invention relates to a displacement sensor device and the system including the device, wherein the device comprises a first at least partially transparent plane surface with a first diffraction pattern and a second plane surface comprising a second reflecting diffraction pattern. The diffractive patterns being adapted to diffract light within a chosen range of wavelengths, the second surface being positioned below and parallel to the first surface constituting a pair wherein said first and second diffractive patterns being essentially equal, the device also comprising displacement means for allowing a movement in a direction parallel to said surfaces, the device thus providing a movement sensitive diffraction pattern.

Abstract: The present invention relates to an optical displacement sensor comprising a first at least partially reflective surface and a second surface having a diffractive pattern, the surfaces being provided on elements having a variable distance between them, each surface pair defining a cavity between them. The sensor also comprising at least one light source transmitting light at least one a chosen wavelength range into said cavities and at least one light detector receiving light from the cavities, wherein said diffractive patterns are adapted to direct light toward at least one detector provided in a known position relative to said diffractive surfaces.

Abstract: An optical microphone arrangement comprises: an array of optical microphones (4) on a substrate (8), each of said optical microphones (4) providing a signal indicative of displacement of a respective membrane (24) as a result of an incoming audible sound; at first processor (12) arranged to receive said signals from said optical microphones (4) and to perform a first processing step on said signals to produce a first output; and a second processor (14) arranged to receive at least one of said signals or said first output; wherein at least said second processor (14) determines presence of at least one element of human speech from said audible sound.

Abstract: The present invention relates to a displacement sensor device and the system including the device, wherein the device comprises a first at least partially transparent plane surface with a first diffraction pattern and a second plane surface comprising a second reflecting diffraction pattern. The diffractive patterns being adapted to diffract light within a chosen range of wavelengths, the second surface being positioned below and parallel to the first surface constituting a pair wherein said first and second diffractive patterns being essentially equal, the device also comprising displacement means for allowing u movement in a direction parallel to said surfaces, the device thus providing a movement sensitive diffraction pattern.

Abstract: The present invention relates to a gas detector cell and cell unit for optical detection of a predetermined gas, the cell being provided with optical means for investigating a gas sample present in the cell. The cell is constituted by a volume enclosed in a container, at least part of the container wall being constituted by a membrane, the membrane being provided with openings allowing diffusion of gas therethrough, and the membrane openings being provided with a catalyst for converting the gas diffusing therethrough to said predetermined gas.

Abstract: The present invention relates to a gas detector cell unit comprising a gas cell, the unit comprising an outer housing providing access to the gas outside through a protecting filter adapted to making gas cell safe for use in explosive environments, i.e. a sintered filter, and the unit comprising means for detecting reduction in the circulation through said protecting filter.

Abstract: The present invention relates to an optical displacement sensor comprising a first at least partially reflective surface and a second surface having a diffractive pattern, the surfaces being provided on elements having a variable distance between them, each surface pair defining a cavity between them. The sensor also comprising at least one light source transmitting light at least one a chosen wavelength range into said cavities and at least one light detector receiving light from the cavities, wherein said diffractive patterns are adapted to direct light toward at least one detector provided in a known position relative to said diffractive surfaces.