LF4 by Sumita

Obsolete Very Rare Environmentally Dangerous

LF4 by Sumita is an obsolete optical glass with a very rare melt frequency. It transmits from 0.31 to 2.00 µm with an nd of 1.57845 and a Vd of 41.7. It has excellent chemical resistance and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.27–2.0 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.27–2.0 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.310–2.000 µm
Optical Properties
Refractive Index (nd) 1.57845
Abbe Number (Vd) 41.7
Dispersion Formula Schott
Wavelength Range 0.27 — 2.0 µm
$$n(\lambda) = \sqrt{2.43632 - 0.0085401\,\lambda^2 + 0.0186639\,\lambda^{-2} + 0.000453007\,\lambda^{-4} + 6.646 \times 10^{-6}\,\lambda^{-6} + 1.60271 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) —
TCE 100/300°C (10-6/K) 9.8
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.2
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 1
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
FL4 Hoya 1.578447 41.707529
FL57 Hoya 1.576163 41.39334
FL7 Hoya 1.57501 41.509668
H-QF3 CDGM 1.57501 41.504715
S-TIL27 Ohara 1.575006 41.505207
LF7 Schott 1.575011 41.490793
PBL27 Ohara 1.575006 41.491052
FL3 Hoya 1.58215 42.028564
QF5 CDGM 1.582153 42.039634
QF3 CDGM 1.575026 41.29692
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LF3 Sumita 1.58215 42.0
LF7 Sumita 1.57501 41.3
LF5 Sumita 1.58144 40.8
LF1 Sumita 1.57309 42.7
LF2 Sumita 1.58921 41.0
LF6 Sumita 1.56732 42.8
F8 Sumita 1.59551 39.2
K-BaSF5 Sumita 1.60323 42.5
BASF5 Sumita 1.60323 42.5
BASF3 Sumita 1.60717 40.2
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