Optical glass type S-FPM5: dn/dT close to zero helps correct temperature drift.

Type Code nc nd nF ng vd s.g. Coloring
S-FPM5 552708 1.54963 1.55200 1.55743 1.56167 70.70 3.74 345/-

An optical glass for polished lenses with a Δn/ΔT that is close to zero.

S-FPM5 is a glass material with a Δn / ΔT closer to zero than conventional FP-based glass materials and is expected to effectively correct refractive index fluctuations (temperature drift) due to temperature changes. In addition, it has a high partial dispersion ratio θg, F, which is a characteristic of FP-based glass materials and is effective for correcting secondary chromatic aberration. This glass material can be used, not only for in-vehicle camera lenses, but also for other applications such as projector and interchangeable lenses.


  • Correct temperature drift
  • Effective when cemented with a lanthanum material lens
  • Effective for correcting secondary chromatic aberration


S-FPM5 (New product)
Classification of environmental measures Environmentally safe
Refractive index nd 1.55200
Abbe number vd 70.70
ΔnT relative D line 40~60℃ -2.8
Partial dispersion ratio θg,F 0.5421
Abnormal dispersibility ⊿θg,F 0.015
CTE α (10 -7 /℃) -30 ~ +70°C 109
+100 ~ +300°C 129
Transition point Tg (℃) 474
Yield point At (℃) 503
Coloring degree λ 80 345
λ 5
Chemical durability RW (P) 1
RA(P) 2
W(S) 1
SR 52.1
PR 4.0
Specific Gravity 3.74
Knoop hardness Hk 410 (4)
Abrasion degree Aa 413
Available Shapes ・Pressings ・Polished Preforms ・Polished Lenses ・Aspherical Glass Mold Lenses