| 摘要 |
<p>PURPOSE:To obtain an infrared type measuring apparatus with high measuring accuracy which prevents an unnecessary light from entering a detector, detects components of the unnecessary light alone and corrects measuring values of the detector by the unnecessary light. CONSTITUTION:A projecting optical system 12 projects infrared rays after modulating the intensity of the rays which enter from an infrared light source 11. In this infrared measuring apparatus, the infrared rays projected from the projecting optical system 12 are cast to an object 14 to be measured, and the passing light or reflecting light from the object 14 is detected by a detector 15 synchronously with the modulation of the intensity, whereby the thickness of the object is measured from the amount of the characteristic absorption in the region of the infrared wavelength of the object, 14. In order to prevent the unnecessary light mixed between the projecting optical system 12 and the detector 15 towards the projecting optical system 12 from entering the detector 15, an optical axis of the optical components of the projecting optical system 12 reflecting the unnecessary light is inclined to the light source and an optical axis connecting the to-be-measured object and the detector.</p> |
