LIGHT IRRADIATION APPARATUS AND INFRARED ABSORPTION TYPE GAS CONCENTRATION MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To conduct gas concentration measurements of high accuracy through infrared absorption in a short time by reducing imbalance quantities of light among the plural systems of a light irradiation apparatus. SOLUTION: Light is incident on a half-mirror 4 from first and second light sources 31a and 32a, and the reflected light component of the first light source 31a and the transmitted light component of the second light source 32a are superimposed one on the other at the half-mirror 4 to obtain the light L1 of a first system; the reflected light component of the second light source 32a and the transmitted light component of the first light source 31a are superimposed one on the other to obtain the light L2 of a second system. Thus, even if there is imbalance in quantity of light between the light sources 31a and 32a due to deterioration, etc., of one of the light sources, deviation of the ratio of the quantity of light of the first system irradiating the interior of a cell 11 having a reference gas sealed therein to the quantity of light L2 of the second system irradiating the interior of a cell 12 into which a sample gas is introduced is reduced to enhance measuring accuracy.