This disclosure provides systems, methods and apparatus for increasing the efficiency of frontlight systems using thin waveguides. In one aspect, a narrowing reflective conduit can be used to condense light from a light source which is thicker than the waveguide, and inject it into the waveguide. A phosphor strip at the exit aperture of the narrowing reflective conduit can inject light with a diffuse directional profile independent of the directional profile of light within the narrowing reflective conduit.