LF7 by Sumita
Obsolete
Very Rare
Environmentally Dangerous
Refractive Index vs Wavelength
Refractive Index Calculator
dn/dλ vs Wavelength
dn/dλ Calculator
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Optical Properties
| Refractive Index (nd) | 1.57501 |
|---|---|
| Abbe Number (Vd) | 41.3 |
| Dispersion Formula | Schott |
| Wavelength Range | 0.27 — 2.0 µm |
$$n(\lambda) = \sqrt{2.42488 - 0.00799679\,\lambda^2 + 0.0188512\,\lambda^{-2} + 0.000431583\,\lambda^{-4} + 8.17937 \times 10^{-6}\,\lambda^{-6} + 1.57205 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
| TCE -30/70°C (10-6/K) | — |
|---|---|
| TCE 100/300°C (10-6/K) | 8.9 |
| 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 | |
|---|---|---|---|---|
| QF3 | CDGM | 1.575026 | 41.29692 | |
| FL57 | Hoya | 1.576163 | 41.39334 | |
| LF7 | Schott | 1.575011 | 41.490793 | |
| PBL27 | Ohara | 1.575006 | 41.491052 | |
| H-QF3 | CDGM | 1.57501 | 41.504715 | |
| S-TIL27 | Ohara | 1.575006 | 41.505207 | |
| FL7 | Hoya | 1.57501 | 41.509668 | |
| FL4 | Hoya | 1.578447 | 41.707529 | |
| LF5HT | Schott | 1.581483 | 40.913786 | |
| LF5HTi | Schott | 1.58144 | 40.89 |