US 3,817,603, sole example — Yasuo Takahashi
| 6 ELEMENTS / 5 GROUPS |
| DESIGN f = 50 mm |
| DESIGN F/1.7 |
| ALL SPHERICAL |
| PATENT f = 100 SCALED × 0.5 |
The patent gives no focus motion: it names no focusing group and publishes the infinity state only, so no element moves in this model. The production lens focuses to 0.45 m; its focus travel is not modeled. The image plane is computed, because the patent prints no back focus.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | TAF5 (HOYA coordinate equivalent; patent νd 46.8 versus catalog 46.6) |
| L2 | Positive Meniscus | TAF5 (HOYA coordinate equivalent; patent νd 46.8 versus catalog 46.6) |
| L3 | Negative Meniscus | SF10 (SCHOTT catalog equivalent; production supplier unspecified) |
| L4 | Biconcave Negative | PBM39 (OHARA catalog equivalent; production supplier unspecified) |
| L5 | Biconvex Positive | TAF5 (HOYA coordinate equivalent; patent νd 46.8 versus catalog 46.6) |
| L6 | Biconvex Positive | TAF5 (HOYA coordinate equivalent; patent νd 46.8 versus catalog 46.6) |