Used with the shorter radius facing the longer conjugate, these lenses（凹凸透镜） act as a focusing element with less aberrations than plano-convex lenses.

产品指标如下：
Diameter tolerance +0,-0.005" (+0,-0.13 mm)
Center Thickness tolerance +/-0.008" (+/-0.2 mm)
Design Wavelength 10.6 microns
Focal Length Tolerance +/-2%
Surface Quality 60/40
Clear Aperture 90% Central Diameter
Wedge Angle <3 arc min
Surface Irregularity 1/20 l at 10.6 microns