The present invention relates to a LED module which converts pump light from a LED chip (120) to light at another wavelength, which is emitted from the module. The conversion takes place in a portion of a luminescent material (124). The color purity of the LED module is enhanced by reducing any leakage of pump light using a reflector in combination with an absorber. In one embodiment, the absorber is integrated as one or several thin absorbing layers between the layers of a multi-layer reflection filter (126); this may yield an even higher reduction of pump light leakage from the module.