Patent ID: 8768600

Claim:
An optical measuring device ( 1 ) for an automotive vehicle, adapted for measuring a spectrum of a light beam, in a wavelength range chosen beforehand, said spectrum being generated by a sample to be analyzed, said optical measuring device comprising: at least one light source ( 12 ); an optic ( 14 ) for forming light rays emitted by said at least one light source ( 12 ); a measurement cell ( 9 ); and a measurement detector ( 17 ) placed on a measurement optical pathway, said measurement optical pathway being taken by a measurement optical beam emitted by the at least one light source ( 12 ), and encountering the measurement cell ( 9 ), a self calibrator allowing any drift of the light source ( 12 ), due to environmental conditions or conditions of use, to be compensated independently of whether a sample to be analyzed is present in or absent from the measurement cell ( 9 ), said self calibrator comprising: means ( 15 ) for creating a reference optical pathway, taken by a reference optical beam emitted by the light source ( 12 ), and not encountering the measurement cell ( 9 ); and a reference detector ( 18 ) that is also the measurement detector ( 17 ), means ( 30 , 31 ) for selectively mixing the measurement optical beam and the reference optical beam, wherein the means for creating a reference optical pathway comprise a first beam splitter ( 15 ), and in that the means for selectively mixing the measurement optical beam and the reference optical beam comprise a second beam splitter ( 31 ) and a beam shutter ( 30 ) that is activated on command, said beam shutter ( 30 ) being placed on the reference optical beam between the two beam splitters ( 15 , 31 ).