CN 211955966 U, Example 1 — Liu Ruijun, Chen Baofeng
| 11 ELEMENTS / 10 GROUPS |
| 50 mm MARKETED / 49.0738 mm MODELED |
| f/1.8 |
| 4 ASPHERICAL SURFACES |
| INNER FOCUS — L31 |
PUBLISHED: G3/L31 alone translates 5.75 mm imageward from infinity to the patent's 0.5 m object-distance state; the patent does not define that distance's reference plane, so this is not asserted as the production sensor-plane MFD.
| Element | Type | Glass |
|---|---|---|
| L11 | Biconcave Negative | Unmatched (nearest 626357 flint family; patent nd≈1.63, νd≈35.7) |
| L12 | Biconvex Positive | M-TAF31 (approximate spectral proxy; patent nd/νd retained; supplier unresolved) |
| L13 | Plano-Convex Positive | M-TAF31 (approximate spectral proxy; patent nd/νd retained; supplier unresolved) |
| L14 | Positive Meniscus | Unmatched (nearest 847238 dense-flint family; patent nd≈1.85, νd≈23.8) |
| L15 | Negative Meniscus | 620363 — flint class (vendor unresolved) |
| L21 | Biconcave Negative | 648339 — dense-flint class (vendor unresolved) |
| L22 | Biconvex Positive | 691548 — lanthanum-crown class (vendor unresolved) |
| L23 | Biconvex Positive (2× Asph) | K-VC89 (catalog-equivalent spectral proxy; supplier unresolved) |
| L31 | Negative Meniscus (2× Asph) | J-FK01A (catalog-equivalent spectral proxy; supplier unresolved) |
| L41 | Biconvex Positive | Unmatched (nd≈1.51, νd≈81.4 low-dispersion crown) |
| L42 | Negative Meniscus | N-SF5 (approximate spectral proxy; patent nd/νd retained; supplier unresolved) |