Abstract: A light unifier, which comprises a plurality of light sources, particularly laser diodes, emitting parallel light beams of a rectangular cross-section, for focusing the light energy of all the beams onto a target area through beam-shaping means, which comprises transverse collimators, means for juxtaposing the emitted beams to form a unified beam, a longitudinal collimator for longitudinally collimating the unified beam, and means for focusing it onto the target area. The light beams have a transverse and a longitudinal divergence and the ratio of the transverse divergence to the longitudinal divergence is higher than 1. The transverse collimators are placed at such a distance from the sources that, at the point at which the beams reach them, the sum of the short sides of the beams is equal to the long side of each of them at the point at which they reach the longitudinal collimator.