Patent ID: 8129480

Claim:
A cured product, obtained by curing a curable polyorganosiloxane composition comprising: (A) alkenyl group-containing polyorganosiloxane which comprises (A1) branched polyorganosiloxane comprising an SiO 4/2 unit and an R 3 SiO 1/2 unit with a molar ratio of R 3 SiO 1/2 unit to SiO 4/2 unit in the range of 1:0.8 to 1:3, and optionally an R 2 SiO unit and/or an RSiO 3/2 unit, wherein at least three R per molecule are alkenyl groups, and 100 mol % of the R, excluding the alkenyl groups, are methyl groups and optionally (A2) linear polyorganosiloxane having R bonded to a silicon atom, wherein at least two R per molecule are alkenyl groups, and 100 mol % of the R, excluding the alkenyl groups, are methyl groups; (B) polyalkylhydrogensiloxane comprising an SiO 4/2 unit and an R 3 (CH 3 ) 2 SiO 1/2 unit with a molar ratio of R 3 (CH 3 ) 2 SiO 1/2 unit to SiO 4/2 unit is in the range of 1.5:1 to 2.2:1, wherein each R 3 represents hydrogen atoms; and (C) a platinum group metal compound, said cured product being an optical lens.