Patent ID: 7444058

Claim:
A resin composition for optical wiring, comprising an inorganic filler with an average particle size of 1 nm to 100 nm and a thermosetting resin, said composition having a ratio n f /n r where (n f is the refractive index of the inorganic filler and n r is the refractive index of the) resin of 0.8 to 1.2, a thermal expansion coefficient of −1×10 −5 /° C. to 4×10 −5 /° C., and a true dependency value of its refractive index on temperature of −1×10 −4 /° C. to 1×10 −4 /° C. in a temperature range from −20° C. to 90° C., and substantially incapable of absorbing light in a wavelength range from 0.6 to 0.9 μm or from 1.2 to 1.6 μm.