FL4 by Hoya

Obsolete Unknown Environmentally Dangerous

FL4 by Hoya is an obsolete optical glass. It transmits from 0.33 to 2.33 µm with an nd of 1.578447 and a Vd of 41.707529. It has dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.334–2.325 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.334–2.325 µm
Abbe Number Calculator
Transmission vs Wavelength

No transmission data available.

Transmission Calculator
Valid wavelength range: 0.334–2.325 µm
Optical Properties
Refractive Index (nd) 1.578447
Abbe Number (Vd) 41.707529
Dispersion Formula Schott
Wavelength Range 0.334 — 2.325 µm
$$n(\lambda) = \sqrt{2.43874 - 0.00980378\,\lambda^2 + 0.016874\,\lambda^{-2} + 0.00106417\,\lambda^{-4} - 8.85701 \times 10^{-5}\,\lambda^{-6} + 6.92066 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) —
TCE 100/300°C (10-6/K) —
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$
Physical Properties
Density (g/cm³) —
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance —
Stain Resistance —
Acid Resistance —
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
LF4 Sumita 1.57845 41.7
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
LF3 Sumita 1.58215 42.0
QF5 CDGM 1.582153 42.039634
LF7 Sumita 1.57501 41.3
QF3 CDGM 1.575026 41.29692
LF5HT Schott 1.581483 40.913786
Similar Glasses (Hoya)
Glass Manufacturer nd Vd Compare
FL57 Hoya 1.576163 41.39334
FL7 Hoya 1.57501 41.509668
FL3 Hoya 1.58215 42.028564
E-FL5 Hoya 1.58144 40.89
FL5 Hoya 1.581437 40.887611
FL1 Hoya 1.573091 42.586108
E-FL6 Hoya 1.56732 42.84
FL6 Hoya 1.567324 42.843119
BAFD16 Hoya 1.6 42.456745
F8 Hoya 1.595514 39.221686
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