A light source for illuminating a selected surface (S), the light source comprising a plurality of Light Emitting Diodes (LED) (E) mounted on a substrate; each of the plurality of LEDs (E) having an optical axis (C) and generating a radiation pattern (P) propagating along the optical axis (C); the plurality of LEDs (E) being arranged so that each optical axis (C) is oriented substantially towards a determined far-field central point; and the plurality of LEDs (E) providing a predetermined irradiance distribution on the selected surface (S); characterised in that the light source is without the need of specific optics, reflectors, mirrors, diffuser, lenses, each of the radiation patterns (P) defines a preferential direction (D), wherein the preferential direction is an orientation of the LED's spatial radiation pattern which is linked to physical and geometrical properties of the LED and is inherent to physical and geometrical constraints in the manufacturing of the LED, and leads the spatial radiation pattern not to be an ideal cone that would be emitted by a point light source, but instead have a spatial radiation pattern that is emitted from an non-punctual shaped light source; and each of the plurality of LEDs (E) is arranged so that the preferential direction (D) of each of the plurality of LEDs (E) is unique, and each angle between two preferential directions (D) is a multiple of 360° divided by a total number of the plurality of LEDs (E). a plurality of Light Emitting Diodes (LED) (E) mounted on a substrate; each of the plurality of LEDs (E) having an optical axis (C) and generating a radiation pattern (P) propagating along the optical axis (C); the plurality of LEDs (E) being arranged so that each optical axis (C) is oriented substantially towards a determined far-field central point; and the plurality of LEDs (E) providing a predetermined irradiance distribution on the selected surface (S); the plurality of LEDs (E) being arranged so that each optical axis (C) is oriented substantially towards a determined far-field central point; and the plurality of LEDs (E) providing a predetermined irradiance distribution on the selected surface (S); characterised in that the light source is without the need of specific optics, reflectors, mirrors, diffuser, lenses, each of the radiation patterns (P) defines a preferential direction (D), wherein the preferential direction is an orientation of the LED's spatial radiation pattern which is linked to physical and geometrical properties of the LED and is inherent to physical and geometrical constraints in the manufacturing of the LED, and leads the spatial radiation pattern not to be an ideal cone that would be emitted by a point light source, but instead have a spatial radiation pattern that is emitted from an non-punctual shaped light source; and each of the plurality of LEDs (E) is arranged so that the preferential direction (D) of each of the plurality of LEDs (E) is unique, and each angle between two preferential directions (D) is a multiple of 360° divided by a total number of the plurality of LEDs (E). the preferential direction (D) of each of the plurality of LEDs (E) is unique, and each angle between two preferential directions (D) is a multiple of 360° divided by a total number of the plurality of LEDs (E). <EOS>