Abstract: A sealed infrared radiation source includes an emitter membrane stimulated by an electrical current conducted through the membrane, which acts like an electrical conductor, wherein the membrane is mounted between first and second housing parts, at least one being transparent in the IR range, each housing part defining a cavity between the membrane and the respective housing part of each side of the membrane. The housing parts are at least partially electrical conductive, and a first of the housing parts is electrically coupled to a first end of the electrical conductor and insulated from the second end of the electrical conductor, the second housing part being electrically coupled to a second end of the electrical conductor and being insulated from the first end of the electrical conductor, thus allowing a current applied from the first housing part to the second housing part to pass through and heat the membrane.

Abstract: A system (10) for automatically inspecting a stream of matter (12) for varying composition, comprising an emitting device (16) serving to emit a detection medium, which comprises electromagnetic radiation of a substantially constant intensity, to an irradiated zone (I) of the stream at which the medium penetrates a surface of the matter (12), the irradiated zone (I) extending continuously across substantially the width of the stream, the medium penetrating the surface being varied by the matter (12), a receiving device (32) for receiving the varied medium emanating from the matter (12) at a detection zone (D) substantially separate from the irradiated zone (I), and a detecting device (34) serving to generate detection data in dependence upon the varied medium, the arrangement being such that, in use of the system (10), at least the majority of the varied medium received at the receiving device (32) can be transflected medium.

Abstract: 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.

Abstract: The present invention relates to an adjustable interference filter, especially for use in gas detection with infrared light within a chosen range, comprising at least two essentially parallel reflective surfaces separated by a chosen distance defining a cavity delimited by the reflective surfaces between which the light may oscillate, and at least one of said surfaces being semitransparent for transmission of light to or from the cavity. The filter comprises a transparent material with a chosen thickness and having a high refractive index positioned in the cavity, and adjustable separation means for adjusting the cavity length between the reflecting surfaces, so as to obtain a cavity constituted by the transparent, high refractive index material and a an adjustable part.

Abstract: A sealed infrared radiation source includes an emitter membrane stimulated by an electrical current conducted through the membrane, which acts like an electrical conductor, wherein the membrane is mounted between first and second housing parts, at least one being transparent in the IR range, each housing part defining a cavity between the membrane and the respective housing part of each side of the membrane. The housing parts are at least partially electrical conductive, and a first of the housing parts is electrically coupled to a first end of the electrical conductor and insulated from the second end of the electrical conductor, the second housing part being electrically coupled to a second end of the electrical conductor and being insulated from the first end of the electrical conductor, thus allowing a current applied from the first housing part to the second housing part to pass through and heat the membrane.

Abstract: A sealed infrared radiation source includes an emitter membrane stimulated by an electrical current conducted through the membrane, which acts like an electrical conductor, wherein the membrane is mounted between first and second housing parts, at least one being transparent in the IR range, each housing part defining a cavity between the membrane and the respective housing part of each side of the membrane. The housing parts are at least partially electrical conductive, and a first of the housing parts is electrically coupled to a first end of the electrical conductor and insulated from the second end of the electrical conductor, the second housing part being electrically coupled to a second end of the electrical conductor and being insulated from the first end of the electrical conductor, thus allowing a current applied from the first housing part to the second housing part to pass through and heat the membrane.

Abstract: A sealed infrared radiation source includes an emitter membrane stimulated by an electrical current conducted through the membrane, which acts like an electrical conductor, wherein the membrane is mounted between first and second housing parts, at least one being transparent in the IR range, each housing part defining a cavity between the membrane and the respective housing part of each side of the membrane. The housing parts are at least partially electrical conductive, and a first of the housing parts is electrically coupled to a first end of the electrical conductor and insulated from the second end of the electrical conductor, the second housing part being electrically coupled to a second end of the electrical conductor and being insulated from the first end of the electrical conductor, thus allowing a current applied from the first housing part to the second housing part to pass through and heat the membrane.

Abstract: 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.

Abstract: The present invention relates to an adjustable interference filter, especially for use in gas detection with infrared light within a chosen range, comprising at least two essentially parallel reflective surfaces separated by a chosen distance defining a cavity delimited by the reflective surfaces between which the light may oscillate, and at least one of said surfaces being semitransparent for transmission of light to or from the cavity. The filter comprises a transparent material with a chosen thickness and having a high refractive index positioned in the cavity, and adjustable separation means for adjusting the cavity length between the reflecting surfaces, so as to obtain a cavity constituted by the transparent, high refractive index material and a an adjustable part.

Abstract: A system (10) for automatically inspecting a stream of matter (12) for varying composition, comprising an emitting device (16) serving to emit a detection medium, which comprises electromagnetic radiation of a substantially constant intensity, to an irradiated zone (I) of the stream at which the medium penetrates a surface of the matter (12), the irradiated zone (I) extending continuously across substantially the width of the stream, the medium penetrating the surface being varied by the matter (12), a receiving device (32) for receiving the varied medium emanating from the matter (12) at a detection zone (D) substantially separate from the irradiated zone (I), and a detecting device (34) serving to generate detection data in dependence upon the varied medium, the arrangement being such that, in use of the system (10), at least the majority of the varied medium received at the receiving device (32) can be transflected medium.

Abstract: This invention relates to an optical displacement sensor element, e.g. for use in a pressure sensor or a microphone, comprising two essentially flat surfaces being separated by a cavity being defined by a spacer, the distance between the surfaces being variable thus providing a displacement sensitive Fabry-Perot interferometer. Both of said surfaces are at least partially reflective, and in that said first surface is provided with at least one optical detector, and one of surfaces being provided on an at least partially transparent material.

Abstract: This invention relates to an optical displacement sensor element, e.g. for use in a pressure sensor or a microphone, comprising two essentially flat surfaces being separated by a cavity being defined by a spacer, the distance between the surfaces being variable thus providing a displacement sensitive Fabry-Perot interferometer. Both or said surfaces are at least partially reflective, and in that said first surface is provided with at least one optical detector, and one of surfaces being provided on an at least partially transparent material.

Abstract: A method and apparatus for identifying a material type in an article, such as wholly or partly transparent bottle of plastic or glass, including, with the aid of a detector station, irradiating the article with rays from an infrared radiation source, detecting rays which have passed through the article non-absorbed, and then carrying out a correlation analysis of such detected rays. The article is made to pass through the detector station in a continuous or discontinuous movement. The rays from the radiation source are successively filtered by the filters consisting of wholly or partly transparent materials which have different spectral characteristics. The rays filtered by the filters and non-absorbed by the article are intercepted in order to form a sequence of measured values representing characteristic transmission signatures of the article. A correlation analysis of the signatures is carried out in relation to statistical models in order to determine the material type of the article.

Abstract: Photo acoustic infrared (IR) detector including a chamber for receiving a gas or gas mixture, a window for allowing pulsed or modulated IR radiation into the chamber, and a pressure sensor adapted to measure pressure changes in the chamber as a consequence of absorbed IR radiation. A generally plate-shaped main part has a recess or bore for substantially forming the chamber whereby the window closes the chamber at one side of the main part and whereby the pressure sensor is of the miniature type and is located at the opposite side of the main part in relation to said one side so that the pressure sensor communicates with and closes the chamber at the opposite side, except for a venting channel for the chamber. A cap is provided at said opposite side of the main part so that it encloses the pressure sensor and forms a gas space communicating with the chamber through the venting channel and being substantially larger than the gas volume in the chamber.

Abstract: A photoacoustic detector including a chamber (1) for receiving the gas, a path for pulsed or modulated IR radiation (2) into, through and out of the chamber, and a pressure sensor (3A-B) adapted to measure pressure changes in the chamber caused by the applied IR radiation. The chamber is formed by joining together at least two major semiconductor elements, in particular, silicon or quartz elements (4A-B) made in planar technology. At least a first element from a major surface (9A-B) has an etched recess which constitutes a substantial proportion of the volume of the chamber. At least one of the elements is provided with a membrane for the pressure sensor, and the space (7) in front of the membrane communicates with the chamber.