LED LIGHT SOURCE

Proposed is a lighting module 100 and an illumination device 200 comprising such a module. The lighting module comprises an array of LEDs 120 mounted on a substrate 110 and an optical structure 130 encompassing the LED array for approximating in operation the LED array as a single homogeneous light source. The optical structure comprises an optical element 140 arranged to provide a luminous intensity profile as a function of a deviation angle a which is substantially constant between −αmax and αmax, wherein αmax is a maximum deviation angle provided by the optical element and substantially zero at angles outside that range. This is especially advantageous for optimizing the trade off between creating a single homogenous light source and maintaining the entendue of the light source. An additional advantage of the optical element 140 is that, except for fresnel reflections on both surfaces, it has no backscattering like a diffuser has, which results in a very low optical loss.