| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable suppression of fall-off in amount of light of measurement light for use in a spectral measurement even if a sample has a refractive power in a spectral transmission measuring instrument, and to enable improvement in measurement accuracy.SOLUTION: Provided are: a collimator lens 2 that converges a light source 1 to form a ray flux L1; a conversion optical system 3 that converges the light flux L1 and forms a parallel ray flux L3 having a ray flux diameter D3 in a smaller diameter than a ray flux diameter D1 of the ray flux L1; a holding base 12 that, when measuring a test lens S, holds the test lens S on an optical path of the parallel ray flux L3; a spectrometer 7 that has a spectrometer opening 6, and measures a spectral characteristic of a converging ray flux L6 incident from the spectrometer opening 6; and a converging lens 5 that is disposed between the holding base 12 and the spectrometer opening 6, converges in each case the parallel ray flux L3 when the test lens S is retreated from the optical path of the parallel ray flux L3 and a transmission ray flux L4 by the parallel ray flux L3 when the test lens S is held on the optical path of the parallel ray flux, and makes the parallel ray flux L3 and the transmission ray flux L4 incident upon the spectrometer opening 6.</p> |
