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S-LAL20 is an optical glass which has negative dn/dT. Cars are used in environments where the temperature change is large from below zero (cold district) to 50 C or above (inside car in summer). In the optical system of Automotive camera lenses, it's common that the focal length is fixed. Since many optical glasses have positive dn/dT, by combining these optical glasses with S-LAL20, it is expected that refractive index fluctuations due to temperature change can be modified efficiently. In addition, S-LAL20 can be used for not only Automotive camera lenses but also projectors, photographic interchangeable lenses and various applications.

1.Negative dn/dT at the region of LAL
    dn/dT(Dline 40℃~60℃) -1.2
2.The highest refractive index among glasses with negative dn / dT at the region of low
    nd approximately 1.7
   (Until now S-PHM52 had the highest nd.   The nd value is approximately 1.62)  

Eco Optical Glass
Refractive Index nd 1.69930
Abbe Number νd 51.11
dn/dT relative
D line 40~60°C
-30~70°C 90
+100~300°C 105
Transformation Point Tg(°C) 628
Yield Point At(°C) 676
Coloring λ80 370
λ5 310
Chemical ResistanceRW(P) 2
RA(P) 4
W(S) 1
SR 53.1
PR 4.2
Specific Gravity 4.38
Knoop Hardness Hk 490[5]
Abrasion Aa 243
Detail Catalog DATA PDF
Available shapes •pressing
•saw cut center-less ground
cylindrical blanks
•cut blanks
Please consult us about available size and tolerance.

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