NOVELTY - Curable silicone resin composition comprises (A) a silicon compound having at least two aliphatic unsaturated radicals and branched or three-dimensional network of an organopolysiloxane, (B) an organosilicon compound having at least two silicon-bonded hydrogen atoms and free of aliphatic unsaturation, in a sufficient amount for the composition to cure in the presence of a hydrosilylation catalyst, (C) a platinum group metal based hydrosilylation catalyst, and (D) silicone powder having an average particle size of 0.5-100 mm, in an amount of 0.1-500 pts. wt of components (A) and (B) combined.    USE - The curable silicone resin composition is useful: for encapsulating optoelectronic semiconductor device (all claimed) including LED, semiconductor laser, photo-diodes, photo-transistors, solar cells, and charge-coupled device; as material for optical devices and optical members; for insulating material for electronic devices and electronic parts; for coating material; and as organic component free flexible encapsulant.    ADVANTAGE - The curable silicone resin composition exhibits high modulus of elasticity, hardness, transparency, gas permeability and brightness extraction efficiency, improved superior light resistance, heat resistance, freeze resistance and electrical insulation, rubber elasticity, material strength, impact resistance, light diffusion and color rendering stabilization, electricity, physical properties, elongation, permeability, heat curability and adhesion.    DETAILED DESCRIPTION - Curable silicone resin composition comprises (A) a silicon compound of formula (SiO((R)3)-(SiO(R)2)m-(SiO(Ar1)2)n-Si(R)3) having at least two aliphatic unsaturated radicals per molecule and branched or three-dimensional network of an organopolysiloxane of formula (R1ap(C6H)qSiO(4-p-q)/2), (B) an organosilicon compound having at least two silicon-bonded hydrogen atoms per molecule and free of aliphatic unsaturation, in a sufficient amount for the composition to cure in the presence of a hydrosilylation catalyst, (C) a platinum group metal based hydrosilylation catalyst, and (D) silicone powder having an average particle size of 0.5-100 mm, in an amount of 0.1-500 pts. wt of components (A) and (B) combined.    R = monovalent hydrocarbon (optionally substituted);    Ar1 = aryl optionally containing heteroatom;    R1a = monovalent hydrocarbon (optionally substituted), alkoxy or OH, 0.1-80 mol% of all silicon-bonded organic radicals being alkenyl;    p, q = positive numbers, where p+q is less than or equal to 1 to less than 2, and p+q is less than or equal to 0.20 to less than 0.95;    m = 0 or 1; and    n = 1.    INDEPENDENT CLAIMS are included for:    (1) a cured product obtained by curing the curable silicone resin composition; and    (2) an optoelectronic semiconductor device obtained by encapsulating an optoelectronic semiconductor element with the curable silicone resin composition and heat curing the composition.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of an optoelectronic semiconductor device.    LED chip (2)    Electrodes (3)    Die bonder (5)    Bonding gold wires (6)    Encapusulating resin composition. (7)