Beam characteristics of optical fibre system using light-emitting diode sources for photographic curing

For photographic curing a liquid monomer, an optical fibre system using 102 4 light-emitting diode (LED) sources is applied. The hitherto unknown chara cteristics of the light were investigated experimentally. The radial intens ity in the light from the LED was distributed in multiple modes. The highes t coupling efficiency was only 2.2%. The intensity distribution was changed considerably through the optical fibres and, at the resin surface, appeare d to correspond approximately to the Gaussian mode. When increasing power b y 37%, the beam diameter increased by 5%. Minor disturbances hardly changed the distribution of power among the fibre's modes.