Schott has introduced optical glasses of the tolerance level 0.5 which it says is an industry first.

The maximum deviation from the nominal values listed in the datasheet is only ± 0.0001, with the refractive index nd and ±0.1 per cent with the Abbe number νd with this new level of quality. This means Schott has the narrowest optical tolerances available in the market, the company says.

Glasses of the tolerance level 0.5 are suitable for use in high precision lenses. To achieve the best possible resolution, several lenses must be precisely in tune with each other. The narrow optical position of the glasses helps to improve the quality of the lenses used in inspection systems in industry or microscopy.

The range of preferred glasses now available supports a wide range of applications. For instance, highly homogeneous N-BK7HT is a typical prism glass. Or N-KZFS, with its abnormal partial dispersion, is used together with the fluorphosphate glass N-FK51A that is known for its low dispersion to perform precise apochromatic colour corrections.