K7 by Sumita

Obsolete Very Rare Environmentally Dangerous

K7 by Sumita is an obsolete optical glass with a very rare melt frequency. It transmits from 0.30 to 2.00 µm with an nd of 1.51112 and a Vd of 60.5. It has excellent chemical resistance and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.27–2.0 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.27–2.0 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.300–2.000 µm
Optical Properties
Refractive Index (nd) 1.51112
Abbe Number (Vd) 60.5
Dispersion Formula Schott
Wavelength Range 0.27 — 2.0 µm
$$n(\lambda) = \sqrt{2.25093 - 0.00783127\,\lambda^2 + 0.012111\,\lambda^{-2} - 7.17126 \times 10^{-5}\,\lambda^{-4} + 3.72202 \times 10^{-5}\,\lambda^{-6} - 1.78826 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) —
TCE 100/300°C (10-6/K) 9.1
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) 2.5
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 Compare
C7 Hoya 1.511122 60.485929
NSL7 Ohara 1.511121 60.485793
H-K6 CDGM 1.511125 60.478905
K7HT Schott 1.511144 60.466081
K7 Schott 1.51112 60.41
B11-60 Corning 1.510999 60.383147
H-K7 CDGM 1.51478 60.634896
N-ZK7A Schott 1.508054 61.04
K4A CDGM 1.50802 61.052897
ZKN7 Schott 1.508469 61.187789
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
BALK3 Sumita 1.51835 60.3
K3 Sumita 1.51823 59.0
K5 Sumita 1.52249 59.6
K11 Sumita 1.50013 61.6
K-PBK50(M) Sumita 1.52025 62.2
KN1 Sumita 1.524 59.3
K-PBK50 Sumita 1.5225 62.3
K-PBK60(M) Sumita 1.52483 62.0
K-PBK40(M) Sumita 1.51497 63.3
K-PBK60 Sumita 1.5274 62.3
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