FD4 by Hoya
Obsolete
Unknown
Environmentally Dangerous
FD4 by Hoya is an obsolete optical glass. It transmits from 0.35 to 1.55 µm with an nd of 1.755199 and a Vd of 27.530242. It has medium thermal expansion (CTE of 7.7×10⁻⁶/K), excellent chemical resistance, and dangerous environmental properties.
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) | 7.7 |
|---|---|
| TCE 100/300°C (10-6/K) | 89.0 |
| Thermal Conductivity (W/mK) | — |
| Heat Capacity (J/gK) | — |
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.03849 \times 10^{-5} + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right]
\Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Chemical Resistance
| Climatic Resistance | 1 |
|---|---|
| Stain Resistance | 0 |
| Acid Resistance | 2 |
| Alkali Resistance | — |
| Phosphate Resistance | — |
Similar Glasses (Other Manufacturers)
| Glass | Manufacturer | nd | Vd | Compare |
|---|---|---|---|---|
| H-ZF6 | CDGM | 1.7552 | 27.530047 | |
| ZF6 | CDGM | 1.755205 | 27.546239 | |
| PBH4 | Ohara | 1.755199 | 27.512146 | |
| PBH4W | Ohara | 1.755199 | 27.512146 | |
| S-TIH4 | Ohara | 1.755199 | 27.512089 | |
| K-SFLD4 | Sumita | 1.7552 | 27.5 | |
| SF4 | Sumita | 1.7552 | 27.5 | |
| SF4W | Sumita | 1.7552 | 27.5 | |
| SF4 | Schott | 1.7552 | 27.58 | |
| D56-27 | Corning | 1.755203 | 27.591377 |