CPC Subgroup
G02B 9/20 the rear component having the compound
Full Title
Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - (G02B15/00 takes precedence) > having three components only > arranged + - + > only one component having a compound lens (G02B9/30 takes precedence) > the rear component having the compound