Illumination system and projection device comprising the same

An illumination system used in a projection device, comprising:

• a light source module comprising a first light source for providing a first light beam of a first waveband;
• a light splitting module comprising:
• a first light splitting element allowing a light beam of the first waveband to pass through, and
• a second light splitting element allowing a light beam of a second waveband to pass through;
• a light consolidating module having a light output surface and a first light input surface, wherein the light consolidating module reflects a light beam having an incident angle greater than a predetermined angel and allows a light beam having an incident angle smaller than the predetermined angel to pass through;
• and
• a waveband converting module comprising a first waveband converting zone;
• wherein, the first light splitting element receives the first light beam and transmits the first light beam to the light consolidating module, the first light beam enters the light consolidating module through the first light input surface, the light consolidating module transmits the first light beam having an incident angle smaller than the predetermined angel to the first waveband converting zone so as to form the first light beam of a third waveband, and the first light beam of the third waveband is transmitted from the waveband converting module to the light consolidating module, and then outputted through the light output surface of the light consolidating module.