JP 2021-189351 A, Example 4 — Keigo Koida
| 6 ELEMENTS / 4 GROUPS |
| f ≈ 41.2 mm |
| F/2.04 |
| 2ω ≈ 55.4° |
| 2 ASPHERICAL SURFACES (HYBRID COMPOSITE) |
Inner focus (IF): G2 (L21–L23) translates 1.21 mm toward the object to the patent's near state (1.28 m, calculated). G1, aperture stop, and G3 remain fixed.
| Element | Type | Glass |
|---|---|---|
| L11 | Biconvex Positive | S-LAH55V (OHARA) |
| L12 | Biconcave Negative | J-SF1 (HIKARI) |
| L21 | Biconcave Negative | 755276 dense-flint class (catalog identity unresolved) |
| L22 | Biconvex Positive | J-LASF015 (HIKARI) |
| L22r | Pos. Meniscus (1× Asph) | UV-curable photopolymer (Nikon) |
| L23 | Positive Meniscus | S-LAH55V (OHARA) |
| L31r | Neg. Meniscus (1× Asph) | UV-curable photopolymer (Nikon) |
| L31 | Biconcave Negative | E-CF6 (HOYA) |