초록 ▼

The present invention relates to a gas cell which is included in a gas sensor and adapted to establish the presence of a gas and/or for determining the concentration of one such gas (G), comprising a cavity (2') which is delimited by wall portions that have light reflecting properties and which is i

The present invention relates to a gas cell which is included in a gas sensor and adapted to establish the presence of a gas and/or for determining the concentration of one such gas (G), comprising a cavity (2') which is delimited by wall portions that have light reflecting properties and which is intended to enclose a volume ((G)) of said gas, and further comprising a light source (3) which is adapted to emit a light bundle (3a') directed for reflection between cavity-associated and opposing wall portions, wherein a light bundle (3a") is comprised of light rays which are reflected in a concave wall mirror surface (2b') and adapted to be directed onto one or more light receivers (4, 5) which function to detect an absorption wavelength corresponding to the gas sample ((G)). The concave curved wall mirror surface (2b') is adapted to reflect an obliquely received divergent light bundle (3a') from the light source (3) onto a flat grating-allocated cavity-associated wall surface (2g') whose reflecting surface includes or is structured as a Littrow arrangement (2g"). The light bundle (3a") is adapted to fall onto the flat wall surface (2g') at an angle which lies close to the Blaze angle of the grating wherewith, inter alia, an absorption wavelength corresponding to the chosen gas sample ((G)) and present in the light bundle (3a") is caused to be reflected and diffracted ((3a")) by said flat wall surface (2g") in a straight opposite direction so as to be reflected again in said curved mirror surface (2b') and directed diffracted towards each of said light receivers (4, 5).

대표청구항 ▼

The invention claimed is: 1. In a gas cell included in a gas sensor and adapted to establish the presence of one or more gases and to determine the concentration of such a gas, wherein the gas cell includes a cavity which is defined by wall portions that have light reflecting properties and which i

The invention claimed is: 1. In a gas cell included in a gas sensor and adapted to establish the presence of one or more gases and to determine the concentration of such a gas, wherein the gas cell includes a cavity which is defined by wall portions that have light reflecting properties and which is intended to enclose a volume of said gas, wherein there is included a light source which is adapted to emit a light bundle directed for reflection between cavity-associated wall portions and opposing wall portions, and wherein the light bundle is comprised of light rays that are reflected in a concave wall portion and directed towards one or more light receivers which are adapted to detect the occurring light intensity in one or more absorbent wavelengths corresponding to the gas, the improvement which comprises in that the concave curved wall portion is adapted to reflect an obliquely received diverging light bundle from the light source on a flat grating-allocated cavity-associated wall portion whose reflective surface presents a Littrow arrangement or a structured Littrow arrangement; in that the light bundle is adapted to fall on said flat wall portion at an angle which lies close to the Blaze angle of the grating; and in that one or more absorption wavelengths in the light bundle corresponding to the gas chosen are caused to be reflected and diffracted by said flat wall portion in a straight opposite direction such that diffracted wavelengths are reflected in said curved surface and directed towards said light receivers. 2. A gas cell according to claim 1, wherein said curved wall portion conforms to a part of a curved shape representing a parabola. 3. A gas cell according to claim 2, wherein the light source appears virtually in or adjacent to a focal point of a parabolic shape. 4. A gas cell according to claim 2, wherein said curved wall portion has the shape of a parabolic arc orientated on one side of the axis of a parabolic shape. 5. A gas cell according to claim 1, wherein the flat grating allocated cavity-associated wall portion includes a grating structure that has a Blaze angle for reflection of light in an opposite direction. 6. A gas cell according to claim 5, wherein the grating structure is adapted to create a diffraction grating solely of a first order and/or of a second order. 7. A gas cell according to claim 1, wherein the Blaze angle is between 50° and 60°. 8. A gas cell according to claim 1, wherein one or more light receivers are placed close to a virtual light source with their receiving lobes directed towards the curved surface. 9. A gas cell according to claim 1, wherein the cavity is formed by at least one polymer based replica that has been treated to give the wall portions light-reflective properties. 10. A gas cell according to claim 1, wherein the light source is comprised of an incoherent light source for generating a wavelength spectrum within the IR range. 11. A gas cell according to claim 1, wherein a light source or virtual light source is placed in or close to a focal point allocated to the concave curved surface. 12. A gas cell according to claim 1, 8 or 11, wherein said one or more light receivers (4, 5 are placed in the close proximity of or in a focal point allocated to the concave curved surface). 13. A gas cell according to claim 1 including a physical light source is placed in one focal point of an elliptical shape and in that a virtual light source appears in the second focal point and is positioned in an opening that includes an optical filter. 14. A gas cell according to claim 13, wherein the optical filter is adapted to allow the passage of light-related wavelengths within a free spectral range applicable to the detector system. 15. A gas cell according to claim 13, wherein the optical filter is adapted to filter out wavelengths that are shorter than wavelengths co-ordinated in the free spectral range. 16. A gas cell according to claim 1, wherein said cavity has the form of two spaces, where one space includes a physical light source and a reflector. 17. A gas cell according to claim 16, wherein said second space serves the function of a measuring chamber that provides light reflections. 18. A gas cell according to claim 17 wherein said measuring path of the measuring chamber is extended by using an optical measuring path inside the first space. 19. A gas cell according to claim 18, wherein said first space includes an inlet and an outlet for the gas (G) to be measured. 20. A gas cell according to claim 16, wherein said first space has a subpart that is partially elliptical in shape. 21. A gas cell according to claim 20, wherein a terminating subpart has a tapering shape. 22. A gas cell according to claim 21, wherein said subpart is delimited by two convergent wall portions. 23. A gas cell according to claim 22, wherein said wall portions are prepared or formed to exhibit deficient reflective properties. 24. A gas cell according to claim 22, wherein said converging wall portions define an angle corresponding to a divergent angle or opening angle for a light bundle emitted from the light source. 25. A gas cell according to claim 1, wherein a plurality of light receivers are co-ordinated on one side of a cavity-associated space. 26. A gas cell according to claim 25, wherein a number of light receivers are co-ordinated on mutually opposite side of said space. 27. A gas cell according to claim 1, wherein said flat grating-allocated cavity-associated wall portion is given a direction in which a virtual extension connects with or passes closely adjacent to the vertex of the concave curved wall portion.