Sinvent As

Gassecure As

Sensibel As

Leland Stanford Junior University

Dräger Safety Ag&co. Kgaa

Sintef Tto As

Håkon Sagberg

Ib-Rune Johansen

Matthieu Lacolle

Olav Solgaard

Odd Løvhaugen

Jakob Vennerød

Knut Sandven

Thor Christian Hobæk

Dag Thorstein Wang

Jon Tschudi

Alain Ferber

Henrik Rogne

Britta Fismen

Sigurd Teodor Moe

Odd Lovhaugen

Britta Grennberg Fismen

Kari Anne Hestnes Bakke

Britta Greenberg-fismen

Niels Peter Ostbo

Lars Borgen

Sigurd T Moe

Niels Peter ØStbØ

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). For the or each interferometric arrangement, when the reflective surface or the diffraction grating is in a zero-displacement position, the optical path length L of the light propagating between the diffraction grating and the reflective surface satisfies the relationship:

Optical displacement sensor

An optical microphone assembly including a substrate having a first and second substrate portions with the first substrate portion being thinner than the second substrate portion, an interferometic arrangement including a membrane and at least one optical element including a surface of the first substrate portion and/or is disposed on a surface of the first substrate portion, and the at least one optical element does not include a diffractive optical element formed as a plurality of holes through the first substrate portion. The optical microphone assembly further includes a light source 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, and with at least one of the first and second paths passing through the first substrate portion, and at least one photo detector arranged to detect at least part of an interference pattern generated by said first and second portions of light dependent on the optical path difference.

Optical microphone substrate

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. 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 such that at least one of the first and second portions is reflected by the reflecting surface of the membrane, 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. The at least one photo detector is arranged to detect at least part of an interference pattern generated by the first and second portions of light dependent on the optical path difference.

Optical microphone assembly

A gas sensor for measuring concentration of a predetermined gas includes a light source () arranged to emit pulses of light, a measurement volume (), a detector () arranged to receive light that has passed through the measurement volume (), and an adaptable filter () disposed between the light source () and the detector (). The gas sensor has a measurement state in which it passes at least one wavelength band which is absorbed by the gas and a reference state in which said wavelength band is attenuated relative to the measurement state. A controller is connected to each of the light source, the detector and the adaptable filter to change the adaptable filter between one of said measurement state and said reference state to the other at least once during a gas sensor operation period.

Gas sensors

An optical microphone assembly including a substrate, an interferometric arrangement, a light source, and at least one photo detector. The interferometric arrangement includes a membrane and at least one diffractive optical element spaced from the membrane. The diffractive optical element(s) include a plurality of lines formed in or disposed on a surface of the substrate and arranged in a first pattern. The substrate includes one or more holes extending fully therethrough, the hole(s) arranged in a second pattern that is different from the first pattern. The light source is arranged to provide light to the interferometric arrangement such that first and second portions of the light propagate along respective, different first and second optical paths via the interferometric arrangement. An optical path difference between the first and second optical paths depends on a distance between the membrane and the diffractive optical element(s). The hole(s) are positioned such that at least one of the first and second optical paths at least partly overlaps with the hole(s). The photo detector(s) are arranged to detect at least part of an interference pattern generated by said first and second portions of light dependent on the optical path difference.

A gas sensor () distinguishes between a target gas and a contaminant and includes a light source (), a measurement volume (), a detector (), and an adaptable filter system () with a first optical filter and a second optical filter. The filter system switches between a first composite state, with both filters in a reference state, a second composite state, with the first filter in a first reference state and the second filter in a second measurement state, a third composite state with the first filter in a first measurement state and the second filter in a second reference state, and a fourth composite state, with both filters in a measurement state. The gas sensor detects a target gas and makes a determination as to a presence of the contaminant by comparing the respective detector signals, generated during at least three of the composite states, with each other.

Gas sensor with two switchable filters and method for operating such a gas sensor

A gas sensor is used for determining a concentration of a predetermined gas in a measurement volume. The gas sensor comprises a light source and a detector arranged to receive light that has passed through the measurement volume. During a first measurement period, the detector is used to make a first measurement of an amount of light received in at least one wavelength band which is absorbed by the gas. The first measurement is compared to a predetermined threshold value. If the threshold is crossed, during a second measurement period the detector is used to make a second measurement of an amount of light received in at least one wavelength band which is absorbed by the gas. The concentration of said gas in said measurement volume is calculated using the first and/or second measurement.

Method and system for gas detection

A gas sensing apparatus () comprises a gas sensor arranged to use light to sense presence of a gas; an optical element () arranged so that said light impinges thereon; and a thermoelectric heat pump () having a cold side () and a hot side (). The thermoelectric heat pump () is configured to transfer heat energy from said cold side () to said hot side () in response to a supply of electrical energy provided to the thermoelectric heat pump (). The hot side () of the thermoelectric heat pump () is in thermal contact with the optical element ().

Optical elements in gas sensors

To achieve gas detection in a precise and reliable way, but at the same time without consuming too much energy, a gas detection system is provided which generally comprises a pair of two different gas detectors. The first detector (D) is active continuously and sense substantially for an unspecific change in the local gas mixture. As a reaction upon the change, the second detector (D) of the pair is activated. This detector (D) performs the determination of the concentration of a specific gas or several specific gasses. The second detector (D) may be of a type which consumes more power, but will be active for a short period of time before returning to an inactive state where only the first detector (D) is active. The first detector (D) however is of a type using little power.

Detector system and method to detect or determine a specific gas within a gas mixture

This invention relates to an interference filter, especially for use in gas detection with infrared light within a chosen range, comprising at least two essentially parallel and partially reflective surfaces with a chosen distance between them thus defining a cavity delimited by the reflecting surfaces between which the light may oscillate, and wherein at least one of said surfaces is partially transparent for transmission of light to or from said cavity. The filter comprises a first transparent material having a high refractive index, e.g. silicon, positioned in at least a part of said cavity, and at least one of said reflective surfaces being divided into a three dimensional pattern with varying shift relative to its plane, thus to provide a position dependent resonance condition between them for separation of different wavelengths in the light.

Interference filter

This invention relates to a configurable diffractive optical element comprising an array of diffractive sub-elements having a reflective surface, wherein each sub-element has a controllable position with a chosen range, and in which a number of sub-elements are provided with a reflective grating with a number of chosen spectral characteristics.

Configurable diffractive optical element

This invention relates to a configurable diffractive optical element comprising an array of diffractive sub-elements having a reflective surface, wherein each sub-element has a controllable position with a chosen range, and in which a number of sub-elements are provided with a reflective grating with a number of predetermined spectral characteristics.

The invention relates an optical displacement sensor element comprising two essentially flat surfaces () being separated by a cavity defined by a spacer () and the surfaces (), the distance between the surfaces being variable, wherein a first of said surfaces () is positioned on an at least partially transparent carrier () and being provided with a reflective pattern, the pattern constituting a pattern being shaped as a diffractive lens, and said second surface () being a reflective surface.

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Oslo, Norway

Håkon Sagberg