WO 2019/220618 A1 — Saburo Masugi, Tomoyuki Sashima
| 12 elements / 9 groups |
| EFL 51.6 mm |
| f/1.85 |
| 2ω = 45.8° |
| 2 Asph · 2 ED |
| MFD 0.4 m |
Patent inner focus: G2 translates 7.911 mm toward the object; G1, stop and G3 stay fixed. Source close distance is 0.4 m object-to-image (307.67 mm to the first surface); the model preserves that object leg after omitting the sensor plate.
| Element | Type | Glass |
|---|---|---|
| L11 | Biconcave Negative | S-TIM25 class (dense flint; patent nd=1.67270, νd=32.2) |
| L12 | Pos. Meniscus (convex to obj.) | FDS18 (HOYA catalog equivalent, 946180; production supplier unspecified) |
| L13 | Pos. Meniscus (concave to obj.) | S-LAL18 class (lanthanum crown) |
| L14a | Thin Aspherical Layer (inferred composite) | Unmatched (patent thin-layer medium; polymer identity and supplier unspecified) |
| L14 | Pos. Meniscus (composite substrate) | S-LAH65V catalog equivalent (production supplier unspecified) |
| L15 | Biconvex Positive (ED) | S-FPM2 / FCD505 class (ED fluorophosphate; patent nd=1.59319, νd=67.9) |
| L16 | Biconcave Negative | S-TIM22 class (dense flint; patent nd=1.64769, νd=33.7) |
| L21 | Biconcave Negative | S-TIM22 class (dense flint; patent nd=1.64769, νd=33.7) |
| L22 | Biconvex Positive (2× Asph) | 774472 - lanthanum dense flint (M-TAF401 code match; patent nd=1.77377, vd=47.2) |
| L23 | Pos. Meniscus (concave to obj., ED) | S-FPL51 / FCD1 class (ED fluorophosphate, νd = 82.6) |
| L31 | Pos. Meniscus (concave to obj.) | FDS18 (HOYA catalog equivalent, 946180; production supplier unspecified) |
| L32 | Neg. Meniscus (concave to obj.) | S-TIM22 class (dense flint; patent nd=1.64769, νd=33.7) |
| L33 | Concave-Plano Negative | S-TIM22 class (dense flint; patent nd=1.64769, νd=33.7) |