IODC 2010 illumination design problem

Problem definition: Transfer maximum monochromatic flux from a 1-mm-square Lambertian source in air to an equal-étendue nonimmersed target. The target surface is rectangular with a 16:9 aspect ratio. The surface area of the target must be at least 4 mm2. The target is defined such that only rays incident on the target surface at angles of θmax or less, relative to the surface normal, are considered to be within the phase space of the target, where the value of θmax is determined by the equal-étendue requirement.