TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The optoelectronic semiconductor is disposed directly on the substrate and the encapsulant is disposed on and encapsulates the optoelectronic semiconductor.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Article: The electronic article further comprises a substrate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The diorganosiloxane units (I) is present in an amount of 79-89 mol.%. The siloxane units (II) is present in an amount of 11-21 mol.%. The linear blocks have an average of 50-400 diorganosiloxane units per linear block.    TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Preparation (M1) of the organosiloxane block copolymer involves: either(1) process (A): reacting linear organosiloxane of formula R1(Z1=N-O)2OSi((R1)2OSiO2/2)nSi(O-N=Z1)2R1 (III) and the organosiloxane resin (II) (10-35 mol.%) in an organic solvent to form the organosiloxane block copolymer; or(2) process (B): reacting linear organosiloxane of formula R1(R1C(O)O)2OSi((R1)2SiO2/2)nSi(O(O)CR1)2R1 (IV) with the organosiloxane resin (II) in an organic solvent to produce a first reaction product and reacting the first reaction product with a silane of formula (R5)qSiX4-q (V) to form the organosiloxane block copolymer.In process (A), the linear organosiloxane (III) is reacted in an amount of 65-90 (preferably 79-89 mol.%) with the organosiloxane resin (II) in an amount of 10-35 (preferably 11-21 mol.%). In the process (B), the linear organosiloxane (IV) is reacted in an amount of 65-90 mol.% with the organosiloxane resin (II) in an amount of 10-35 mol.% to produce the first reaction product. The first reaction product is reacted in an amount of 90-99.9 mol.% with the silane (V) in an amount of 0.1-10 mol.%. The process (A) and (B) further involves: removing the organic solvent; reacting the organosiloxane block copolymer with an alcohol having 1-10C to form an alkoxy-capped organosiloxane block copolymer.Z1==C(R1)2 or =CR4;R4=hydrocarbylene;n=100-400;R5=1-8C hydrocarbyl or 1-8C halogen-substituted hydrocarbyl;X=hydrolyzable group;q=0-2.Preferred Components: The organosiloxane block copolymer is a sheet. The encapsulant is cured. The substrate comprises the organosiloxane block copolymer. Preferred Definitions:    x=0.8-1.2;    y=0-0.2;    R1=methyl;    R2=aryl;    R3=H.    EXAMPLE - Organosiloxane block copolymer was formed using oxime terminated PDMS and had approximately 11 mol.% of phenyl-T units which corresponds to 20 wt.% of phenyl-T units. 1L3-Neck round bottom flask was loaded with a phenylsilsesquioxane hydrolyzate (Dow Corning 217 Flake, 24 g) and toluene (80 g) to form a mixture. The flask was equipped with a thermometer, Teflon stir paddle, and a Dean Stark apparatus pre-filled with toluene and attached to a water-cooled condenser. A nitrogen blanket was then applied. An oil bath was used for heating. The mixture was heated at reflux for 30 minutes and cooled to 100 degrees C. At this point, a solution of oxime capped polydimethylsiloxane (PDMS), formed using the method described above, was added. More specifically, the oxime capped PDMS was formed using toluene (200 g), silanol terminated PDMS (96 g), Gelest DMS-S27 184 dp and 4.46 g methyltris(methylethylketoxime)silane (MTO) from Gelest. The oxime-PDMS was added quickly to the phenylsilsesquioxane hydrolyzate at 100 degrees C, heated at reflux for 2.5 hours after which n-butanol (12 g) was added and further heated at reflux for another 3 hours. At this point, some volatiles were then removed by distillation to increase a solids content to 40 wt.%. Subsequently, the mixture was cooled to room temperature. The organosiloxane block copolymer formed was optically clear and colorless. Cast sheets were then formed by pouring the organosiloxane block copolymer onto a flat surface and evaporating the solvent overnight at room temperature. The cast sheets appeared optically hazy/cloudy. After formation, the organosiloxane block copolymer was analyzed by 29Si NMR which confirmed a structure of (Me2SiO2/2)0.010(MeSiO2/2) 0.110(PhSiO3/2)0.110. The sheet had phenyl-T of 20 wt.%, phenyl-T of 11 mol.%, approximate linear segment Dp of 184, approximate tensile strength of 1.55 Mpa, approximate elongation at break of 154%, approximate tear strength of 4 Kn/M, approximate store A hardness of 26 and approximate refractive index of 1.430 and with translucent appearance.