| 摘要 |
PROBLEM TO BE SOLVED: To provide an absorbance measuring instrument capable of detecting an absorbance of a measured sample with high sensitivity. SOLUTION: In this absorbance measuring method, an absorbance distribution 8 wherein the absorbance varied continuously between a band of a relatively high absorbance and a band of a low absorbance is formed to generate lens action based on diffraction of light, a photodetector 4 is provided in an image-focusing position of diffracted light of the light emitted from a light source 1 toward a sample plate 3 to measure the absorbance. In this absorbance measuring instrument, the ring-like absorbance distribution 8 is formed by providing a concentric-circular top part and bottom part, by reducing a ridge height in accompaniment to separation of a cross-sectional shape to get distant radially from the center in order to dissipate secondary or more diffraction light, and by narrowing a pitch interval of the top part to converge the diffraction light in one point, so as to overlap the measured sample 5 and a standard sample 6 via a partitioning film 7, an image-focusing lens 2 is provided between the light source 1 and the sample plate 3, and the light source 1 and the photodetector 4 are provided coaxially on an optical axis. COPYRIGHT: (C)2005,JPO&NCIPI
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