An achromatic-doublet consists of a positive low-index(crown glass)cemented with a negative high-index(flint glass)lens. These lenses are computer-optimized for infinite conjugate ratio. They also exhibit excellent paraxial performance, with minimal spherical aberration, coma and chromatic aberration. When used for imaging, the convex lens should face the object or the image that is furthest away.
• Focal Length (f'): ±2% at 587.6nm
• Diameter(φ) Tolerance: +0.0/-0.20
• Center Thickness(Tc): ±0.1
• Centration: 3′
• Form Error: 1~5 fringes
• Irregularity of Fringes: 0.2~0.5 fringes
• Surface Quality: 60-40 scratch-dig
• Coating: 1/4 wave MgF2 coating at 550nm for 0° angle of incidence
• Clear Aperture: 90% diameter