Four-lens cemented lens

Afour-lens is cemented by one piece of crown glass with low refractive index and two piece of flint glass with high refractive index, normally the cemented lens can eliminate spherical chromatic aberration of axial direction. Because the design of these lenses are complete symmetrical, so they can be used by changing-over. The commonly used materials include crown glass and flint glass. Specifications: Material: grade A optical glass or Fused Silica Diameter: from 0.8mm to 5.0mm Diameter Tolerance: +0.0, -0.1mm(Standard), +0.0, -0.02mm(Precision) Paraxial Focal Length: +/-2% Centration: 5 arc minutes Clear Aperture: >85% of diameter Surface Figure: lambda/4 at 632.8nm Surface Quality: 40-20 S/D 10-5(Precision) Bevel: 0.25x45deg