FD41 by Hoya

Obsolete Unknown Environmentally Dangerous
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.

Optical Properties
Refractive Index (nd) 1.750839
Abbe Number (Vd) 27.686615
Dispersion Formula Schott
Wavelength Range 0.334 — 2.325 µm
$$n(\lambda) = \sqrt{2.95241 - 0.0117784\,\lambda^2 + 0.0326389\,\lambda^{-2} + 0.00331266\,\lambda^{-4} - 0.000292297\,\lambda^{-6} + 2.63697 \times 10^{-5}\,\lambda^{-8}}$$
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
SFN4 Sumita 1.7506 27.8
SF63 Schott 1.7484 27.713565
D56-27 Corning 1.755203 27.591377
SF4 Schott 1.7552 27.58
ZF6 CDGM 1.755205 27.546239
H-ZF6 CDGM 1.7552 27.530047
PBH4W Ohara 1.755199 27.512146
PBH4 Ohara 1.755199 27.512146
S-TIH4 Ohara 1.755199 27.512089
SF4W Sumita 1.7552 27.5
Similar Glasses (Hoya)
Glass Manufacturer nd Vd
FD4 Hoya 1.755199 27.530242
E-FD4 Hoya 1.7552 27.53
E-FD4L Hoya 1.7552 27.53
FD13 Hoya 1.740774 27.764991
E-FD13 Hoya 1.74077 27.76
FD3 Hoya 1.739999 28.245048
FDS5 Hoya 1.761804 26.914901
FD140 Hoya 1.76182 26.61
FD14 Hoya 1.761823 26.552048
FF8 Hoya 1.75211 25.05
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