S-LAL20 which has negative dn/dT at the field of low dispersion and is ideal for polished lenses of Automotive cameras.
05.31.2017
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.
(Advantages)
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
dispersion
nd approximately 1.7
(Until now S-PHM52 had the highest nd. The nd value is approximately 1.62)
| S-LAL20 | ||
| Eco Optical Glass | ○ | |
| Refractive Index nd | 1.69930 | |
| Abbe Number νd | 51.11 | |
| dn/dT relative D line 40～60℃ |
-1.2 | |
| CTE α (10-7/℃) |
-30～70℃ | 90 |
| +100～300℃ | 105 | |
| Transformation Point Tg(°C) | 628 | |
| Yield Point At(°C) | 676 | |
| Coloring | λ80 | 370 |
| λ5 | 310 | |
| Chemical Resistance | RW(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 | ||
| Available shapes | •pressing •saw cut center-less ground cylindrical blanks •cut blanks |
|
Please consult us about available size and tolerance.