Similar refractive index as S-PHM52 with improved processability and chemical durability.

Improved Processability and Chemical Durability

S-PHM52Q is an optical glass with the same refractive index as S-PHM52 and nearly the same abbe number. Optical materials in the PHM region are generally characterized by a large, negative dn/dT value. However the dn/dT value of S-PHM52Q is actually close to 0, enabling an optical design that suppresses the effects of temperature drift. In addition, while S-PHM52 has the lowest dispersion and largest number of relative partial dispersion deviation of ⊿θg, F in nd ≒ 1.62, it is also soft, relatively fragile, and easily scratched. S-PHM52Q has improved workability and chemical durability while maintaining the same basic optical properties. (maximum THK is 35mm)


  • Improved chemical durability: 
    Water Resistance [RW(p)]: Class 1, Acid Resistance[RA(p)]: Class 3
  • Improved mechanical durability Abrasion (Aa): 313
  • The dn/dT value is close to 0 dn/dT
    (Dline 40℃~60℃): -0.7×10-6/℃
  • Low specific gravity (conventional ratio): 3.51


Type Code nc nd nF ng vd s.g. Coloring
S-PHM52Q 618633 1.61550 1.61800 1.62479 1.63008 63.32 3.51 365/325