Abstract: A light distributor is described for use in distributing light from a source in a generally uniform manner across an edge, to for example, illuminate an array of light sensitive elements. The light distributor can be made of a transparent plastic material and is formed with a light guide and a lamp supporting segment. The light guide has a pair of planar faces bounded by sides of a curvature, which bears a particular relationship with a light source region in the lamp supporting segment so as to distribute light therefrom across the edge. A cost effective efficient light distributor is described, particularly for use in activating photocells arranged in an array in a shaft encoder.