8.7 Fine Gob (FG)
We supply small diameter pre-formed "Fine Gobs" suitable for mould pressing into commercial lenses. FG is produced by direct moulding of molten glasses with low softening properties. Shape of standard FG is convex on both sides as shown in the sketch below.
| Fig. 7 |
Table 16 shows the current supply sizes for FG. When ordering, please specify necessary dimensions such as diameter, centre thickness and radius of curvature. Optical properties (refractive indices, Abbe number, etc.) will change depending on thermal conditions during mould pressing. Refractive indices of FG products will be within the tolerances shown in this catalogue when FG is heat-treated using conditions stipulated by OHARA.
| Volume (cc) | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 |
| Diameter (mm) | 6.0 ~ 6.5 | 7.5 ~ 8.5 | 9.0 ~ 10.0 | 11.0 ~12.5 | 12.0 ~ 14.5 |
| Central thickness (mm) | 4.5 ~ 5.0 | 5.5 ~ 6.5 | 6.0 ~ 7.0 | 7.0 ~ 8.0 | 7.5 ~ 8.5 |
| R1 (mm) | 3.0 ~ 4.5 | 4.5 ~ 5.5 | 6.0 ~ 7.5 | 8.5 ~ 11.0 | 12.0 ~ 17.5 |
| R2 (mm) | 3.0 ~ 4.5 | 4.5 ~ 7.0 | 5.0 ~ 8.5 | 6.0 ~ 10.0 | 6.5 ~ 12.0 |
| Table 16 |
Figures of R1 and R2 are radius curvatures within the scope of diameter 4 mm.