US 5,760,973 — Atsushi Kawamura
| 7 ELEMENTS / 4 GROUPS |
| f ≈ 28.1 mm |
| F/2.86 |
| 2ω ≈ 74.4° |
| 2 ASPHERICAL SURFACES |
Inferred unit focus: all four components and the stop move objectward 2.762 mm at the modeled 0.35 m object-to-image endpoint. The patent gives no finite-focus schedule; intermediate distance labels are approximate.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconcave Neg. (1× Asph) | SF2 (catalog equivalent; production supplier unspecified) |
| L2 | Biconvex Positive | S-LAM54 (catalog equivalent; production supplier unspecified) |
| L3 | Negative Meniscus | E-FD8 (catalog equivalent; production supplier unspecified) |
| L4 | Biconcave Negative | FK5 (catalog equivalent; production supplier unspecified) |
| L5 | Biconvex Positive | S-LAH55 (catalog equivalent; production supplier unspecified) |
| L6 | Negative Meniscus | E-FD13 (catalog equivalent; production supplier unspecified) |
| L7 | Neg. Meniscus (1× Asph) | F5 (catalog equivalent; production supplier unspecified) |