JP H05-042643 B2, Example 1 — Masaki Imaizumi
| 10 ELEMENTS / 8 GROUPS |
| DESIGN f = 100 (NORMALIZED; SCALED 1.8× TO 180 mm) |
| DESIGN F/2.0 |
| ALL SPHERICAL |
| INTERNAL FOCUS |
Internal focus: the negative singlet IIa and the cemented pair IIb (with the stop) both move toward the image, IIb slightly farther, while the front and rear groups stay fixed. The patent prints the gaps at infinity and at object points 3056 and 1031 (patent units, about 5.5 m and 1.86 m from the front vertex at 180 mm). Intermediate states follow a quadratic IIa/IIb travel law through those rows; the 1.6 m minimum focus distance extrapolates past the last printed state.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | FCD1 (HOYA catalog equivalent; production supplier unspecified) |
| L2 | Positive Meniscus | S-PHM51 (OHARA catalog equivalent; production supplier unspecified) |
| L3 | Biconcave Negative | BPH5 (OHARA catalog equivalent; production supplier unspecified) |
| L4 | Positive Meniscus | FCD1 (HOYA catalog equivalent; production supplier unspecified) |
| L5 | Biconcave Negative | BSL21 (OHARA catalog equivalent; production supplier unspecified) |
| L6 | Biconvex Positive | S-TIM28 (OHARA catalog equivalent; production supplier unspecified) |
| L7 | Biconcave Negative | Unmatched (patent nd=1.52682, νd=51.12; recurs in Example 2; nearest catalog CF2/KF2 at nd 1.52630 is outside source precision) |
| L8 | Biconvex Positive | S-LAH64 (OHARA catalog equivalent; production supplier unspecified) |
| L9 | Biconcave Negative | E-F5 (HOYA catalog equivalent; production supplier unspecified) |
| L10 | Biconvex Positive | S-LAL12 (OHARA catalog equivalent; production supplier unspecified) |