Light transmission control apparatus

Claim 1

A solar switch for controlling the transmission of solar energy to the location where the transmitted solar energy is utilized, comprising converging means for converging the sunlight into light having a high energy density, a first optical cable into which the sunlight is converged by said converging means, said first cable having an end face, a second optical cable having an end face, said two end faces being spaced from one another at a predetermined spacing, said first and second cables defining an optical path for introducing and passing therethrough said converged light of high energy density, a light interceptor means comprising isotropic graphite disposed in a plane perpendicular to said optical path and movable between a first position within said space between said first and second end faces for blocking said optical path and a second position removed from said space for unblocking said optical path, said light interceptor means having a channel, at least one of said end faces being disposed within said channel to thereby prevent leakage of light when the solar switch is in said first position blocking said path, whereby said light interceptor means thereby functions as a solar switch for controlling the transmission of solar energy to said location where the solar energy is utilized.