Patent ID: 8450445

Claim:
A method of making a light emitting diode (LED) having an optical element, comprising: providing a curable liquid polysiloxane/TiO 2 composite, comprising: (a) providing: (i) D units having a formula R 1 (R 2 )Si(OR 6 ) 2 ; (ii) T units having a formula R 3 Si(OR 7 ) 3 ; (iii) optionally, M units having a formula R 4 3 SiOR 8 ; and, (iv) optionally, Q units having a formula Si(OR 9 ) 4 ; wherein each R 1 and R 3 is independently selected from a C 6-10 aryl group and a C 7-20 alkylaryl group; wherein each R 2 is a phenoxyphenyl group; wherein each R 4 is independently selected from a C 1-10 alkyl group, a C 7-10 arylalkyl group, a C 7-10 alkylaryl group and a C 6-10 aryl group; wherein each R 6 , R 7 , R 8 and R 9 is independently selected from a hydrogen atom, a C 1-10 alkyl group, a C 7-10 arylalkyl group, a C 7-10 alkylaryl group and a C 6-10 aryl group; and wherein each R 6 , R 7 , R 8 and R 9 is independently selected from a hydrogen atom, a C 1-10 alkyl group, a C 7-10 arylalkyl group, a C 7-10 alkylaryl group and a C 6-10 aryl group; wherein the D units contain >1 ppb to ≦100 ppm in combined total of all target contaminants having formulae selected from R 1 —O—(R 2 )Si(OR 6 ) 2 ; R 2 —O—(R 1 )Si(OR 6 ) 2 ; R 1 (R 10 )Si(OR 6 ) 2 ; and, R 2 (R 11 )Si(OR 6 ) 2 ; wherein R 10 is selected from a phenol-oxy-phenyl group and a phenyl-oxy-(hydroxy)phenyl group and wherein R 11 is a hydroxyphenyl group; (b) combining in an aprotic solvent the D units, the T units, any optional M units and any optional Q units; (c) adding to the combination of (b) an acid in a miscible mixture of water and an alcohol to form a reaction mixture; (d) allowing the reaction mixture to react; (e) adding an organo-titanate in an aprotic solvent to the reacted reaction mixture of (d); (f) adding water to the product of (e); (g) heating the product of (f) and allowing it to react; and, (h) purifying the product of (g) to provide the curable liquid polysiloxane/TiO 2 composite; wherein the curable liquid polysiloxane/TiO 2 composite exhibits a refractive index of >1.61 to 1.7 and wherein the curable liquid polysiloxane/TiO 2 composite is a liquid at room temperature and atmospheric pressure; providing a semiconductor light emitting diode die having a face, wherein the semiconductor light emitting diode die emits light through the face; contacting the semiconductor light emitting diode die with the curable liquid polysiloxane/TiO 2 composite; and, curing the curable liquid polysiloxane/TiO 2 composite to form an optical element; wherein at least a portion of the optical element is adjacent to the face.