Patent ID: 7564558
Filing Date: 2009-07-21
Classification: G01J,G01N

Abstract:
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.