10.4 Refractive Index (ni) Variation within one Lot (Sn Standard)
The indicated Sn value is the refractive index variation after annealing within a single batch (same melt, same annealing run).
10.5 Refractive Index Tolerance
The standard refractive index (ni) of our i-line glasses is higher than our catalogue nominal values. This is due to the longer annealing times which are necessary to obtain the desired homogeneity levels. Longer annealing times result in higher refractive indices.
| Fig. 9 |
Example: +20±30×10-5
+20 (+0.00020) means the increase against our catalogue nominal ni value. The ±30 (±0.00030) is then the tolerance on the new nominal value. i.e. a glass type having a tolerance of +20±30 can vary from -10 (-0.00010) to +50 (+0.00050) against standard catalogue nominal. Please consult us when tighter tolerances are required.