A lens consisting of two elements, usually of a positive low-index (crown) and a negative high- index (flint) lens.
Excellent paraxial performance, minimal spherical aberration, coma and smallest chromatic aberration.
Corrected for chromatic aberration with respect to two selected wavelength.
Manufacturing Tolerances
Attribute |
Commercial standard |
precision Standard |
Material |
Optical glass (Crown and flint) |
Optical glass (Crown and flint) |
Diameter (Φ) |
+0.00/-0.50 |
+.0.00/-.20,-0.15 |
Effective Focal Length (f) |
±5% |
±2%,±1% |
Irregularity of Fringes |
0.5 |
0.2 |
Surface Quality |
λ / 2, λ/4 |
λ / 4, λ/10 |
Cosmetics (Scratch-dig) |
80-50,60-40 |
20-10,10-5 |
Center Thickness(t)(mm) |
±0.25% |
±1 |
Centering Error (arc min) |
3 |
2,1 |
Clear Aperture |
80% of diameter |
90% of diameter |
Bevel (mm) |
Fine ground, beveled |
Fine ground, beveled |
Coating |
See attached coating chapter. |
See attached coating chapter. |
All dimensions are in mm unless otherwise specified.
Different material, sizes, tolerance and coating are available upon request.
