K-LaK12 by Sumita
Standard
Medium
Environmentally Friendly
K-LaK12 by Sumita is a standard optical glass with a medium melt frequency. It transmits from 0.31 to 2.00 µm with an nd of 1.6779 and a Vd of 55.5. It has medium thermal expansion (CTE of 6.9×10⁻⁶/K) and good chemical resistance.
Refractive Index vs Wavelength
Refractive Index Calculator
dn/dλ vs Wavelength
dn/dλ Calculator
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Optical Properties
Thermal Properties
| TCE -30/70°C (10-6/K) | 6.9 |
|---|---|
| TCE 100/300°C (10-6/K) | 8.1 |
| Thermal Conductivity (W/mK) | — |
| Heat Capacity (J/gK) | — |
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-3.52 \times 10^{-6} + 2(1.96 \times 10^{-8})\,\Delta T + 3(-6.9 \times 10^{-11})\,\Delta T^2 + \frac{5.11 \times 10^{-7} + 2(4.65 \times 10^{-10})\,\Delta T}{\lambda - 0.152}\right]
\Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Chemical Resistance
| Climatic Resistance | 1 |
|---|---|
| Stain Resistance | — |
| Acid Resistance | 3 |
| Alkali Resistance | — |
| Phosphate Resistance | — |
Similar Glasses (Other Manufacturers)
| Glass | Manufacturer | nd | Vd | Compare |
|---|---|---|---|---|
| H-LAK5A | CDGM | 1.6779 | 55.51497 | |
| LAC12 | Hoya | 1.6779 | 55.52 | |
| C78-56 | Corning | 1.678004 | 55.519168 | |
| S-LAL12Q | Ohara | 1.6779 | 55.346888 | |
| S-LAL12 | Ohara | 1.6779 | 55.341195 | |
| LAL12 | Ohara | 1.6779 | 55.337587 | |
| N-LAK12 | Schott | 1.6779 | 55.2 | |
| LAKN12 | Schott | 1.6779 | 55.199566 | |
| LAKL12 | Schott | 1.6779 | 54.92 | |
| D-LAK5 | CDGM | 1.6779 | 54.889665 |