Optical glass type S-LAL20: highest refractive index among glass types with negative dn/dT in -LAL family.

Type Code nc nd nF ng vd s.g. Coloring
S-LAL20 699511 1.69520 1.69930 1.70888 1.71647 51.11 4.38 370/310

S-LAL20 has negative dn/dT

S-LAL20 is an optical glass with negative dn/dT. In Automotive camera lens systems, the focal length is often a fixed distance. Refractive index fluctuations within the optical system should certainly be a consideration, as cars are used in environments where the temperature range can vary widely from below zero in colder climates to more that 50°C inside a car on a summer day. Since many optical glasses have positive dn/dT values, the refractive indices fluctuations due to temperature change can be adjusted efficiently when these materials are combined with S-LAL20. In addition to Automotive camera lens systems, S-LAL20 can also be used for Projectors, Interchangeable Photographic lenses, and various other applications.


  • Negative dn/dT
  • The highest refractive index among glasses with negative dn/dT in LAL optical region