Patent ID: 7643860

Claim:
A portable instrument, for measuring a physiological quantity, adapted to be brought into contact with a surface of an organic tissue, the portable instrument including, essentially arranged in a same plane: an illumination device including at least one light source with a determined illumination surface for subjecting a portion of the organic tissue to a light emission in at least one determined wavelength range; and a detection device distant from said illumination device for detecting intensity of the light emission produced by said illumination device after propagation in the organic tissue, wherein said illumination device further includes an optical element forming a guide having at least two portions at different orientations in the plane coupled to said at least one light source for guiding the light emission from said source by total internal reflection in a substantially parallel direction to the surface of the organic tissue to be illuminated and for distributing the light emission into several determined illumination zones on the surface of the organic tissue over a substantially broader area than the illumination surface of said light source.