| 摘要 |
PURPOSE:To make it possible to measure the uniformity of a refractive index with high accuracy without depending on the diameter and thickness of a glass material, by forming a pervious surface and a reflective surface, both of which have a high flatness degree, by the surfaces of first and second liquid layers and supporting the glass material. CONSTITUTION:Mercury 8 having light reflectivity and density higher than that of a glass material 1 and oil 2 having a refractive index near to that of the glass material and low in density as compared with said glass material are stored in a tank 7. The glass material 1 having oil 2 preliminarily adhered to both polished surfaces thereof is put in the tank 7 and a screw rod 10 is regulated in such a state hat the glass material is floated at the middle position between two layers to allow the glass material 1 to be stationary so as not to move to a horizontal direction. A plane wave is transmitted through the glass material 1 and reflected from the liquid surface of mercury 8 below the glass material 1 while the relative phase shift quantity of the transmitted plane wave, which was again transmitted through the glass material and returned, is measured by a phase interference measuring machine 6 to calculate the homogeneity (uniformity of refractive index) of the glass material 1. |
