LLF4 by Sumita

Obsolete Very Rare Environmentally Dangerous

LLF4 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 1.56138 and a Vd of 45.3. It has good 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) 1.56138
Abbe Number (Vd) 45.3
Dispersion Formula Schott
Wavelength Range 0.27 — 2.0 µm
$$n(\lambda) = \sqrt{2.38964 - 0.0087285\,\lambda^2 + 0.0164036\,\lambda^{-2} + 0.000458271\,\lambda^{-4} - 8.99592 \times 10^{-6}\,\lambda^{-6} + 2.01712 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) —
TCE 100/300°C (10-6/K) 10.0
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) 3.04
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 2
Stain Resistance —
Acid Resistance 1
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
FEL4 Hoya 1.561379 45.226718
LF8 Schott 1.564435 43.75028
IRG7 Generic IR 1.564424 43.736647
LLF7 Schott 1.548831 45.40834
FEL7 Hoya 1.54883 45.439785
PBL7 Ohara 1.548689 45.555746
FEL3 Hoya 1.560125 47.090971
PBL1Y Ohara 1.548141 45.733282
B48-46 Corning 1.548098 45.718533
LLF1 Schott 1.54814 45.75
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LLF7 Sumita 1.54869 45.4
LLF1 Sumita 1.54814 45.9
LF6 Sumita 1.56732 42.8
LF1 Sumita 1.57309 42.7
BAF3 Sumita 1.58267 46.5
BAF1 Sumita 1.5569 48.5
LLF2 Sumita 1.54072 47.2
LLF8 Sumita 1.53256 46.0
LF4 Sumita 1.57845 41.7
LF3 Sumita 1.58215 42.0
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