Patent ID: 7001066

Claim:
A waveguide for an infrared thermometer comprising: a tubular body having an inner surface defining a communicating passage between a first and a second opening of the tubular body opposite each other, said inner surface having at least one portion converging in the direction of the second opening, said convergent portion comprising at least two axially consecutive lengths in which the length closer to the second opening has a greater convergence than the other length, said convergent portion of the inner surface having a convergence progressively and continuously increasing from said first opening towards said second opening limited by respective borders, said second opening being interposed between the first opening and one sensor member of infrared-radiation intensity disposed outside the wave-guide, said inner surface defining in longitudinal section curved lines which are symmetrically opposite with respect to the longitudinal symmetry axis of the tubular body itself, said opposite curved lines converging progressively and in a manner increasingly more marked on moving from said first opening towards said second opening, each of said curved lines being a conic section.