Lightweighted mirror substrates
Near net shape plano-concave round mirror substrates with an diameter from 10 to 28 inch are available. Edge thickness ranges from 45mm to 55mm. Focal ratio F3.3 to F5. The areal density of our standard mirror blank is 30Kg/m2 targeting for an areal density of ~25Kg/m2 for the finished mirror. The high number of support elements eliminates print through issues during conventional polishing to small amount (<1/40rms/wave). The distribution of support elements is FEM optimized for minimal wavefront abberation due to gravity loads in the finished mirror.
Our standard line of mirror blanks are available in two different glass types with characteristic thermal expansions. All glass types are suitable for a precision optical surface.
Material: Soda-lime glass [density ~ 2.5g/cm3, thermal Expansion 7.6x10-6m/m/K [-18C°+20C°]
Plate thickness: 6mm for front and back plate
Material: Borosilicate glass [density ~ 2.2g/cm3, thermal expansion 3.2x10-6m/m/K [-18C°+20C°]
Plate thickness: 6.5mm for front and back plate
Diameter [inch]: 10", 12", 14", 16", 18", 20", 22", 24", 26". Tolerance: +2mm/-2mm
Thickness at the edge: 40mm to 51mm depending on the Diameter
Number of support Elements FEM optimized 61 to 219 depending on the Diameter
Example 10" ~ 1,5KG; 26" ~ 10,3KG (mass of the blank SG-L before optical processing which typical reduces the mass by another ~10%)
Formula: Radius x Pi x thickness (front+backplate) x density