Light source

A light source, comprising:

• a light-emitting device to emit electromagnetic radiation from an emitting surface;
• and
• an optical element having a light input surface, a light output surface, and side surfaces connecting the light input surface to the light output surface;
• wherein:
• the entire light input surface is located in the optical path of the light-emitting device, in front of the emitting surface, so that the electromagnetic radiation enters the optical element through the light input surface;
• the light input surface has a concave curvature and an area smaller than an area of the light output surface;
• the entire light input surface is separated from the emitting surface by a distance greater than or equal to about 0.8 mm and less than or equal to about 2 mm, forming a gap between the light-emitting device and the optical element;
• and
• a first bluish part of the electromagnetic radiation directly and completely illuminates the entire light output surface;
• and
• a second yellowish part of the electromagnetic radiation completely illuminates the entire light output surface after being reflected by the side surfaces towards the light output surface.