Illumination system and projection device

A projection device, comprising an illumination system, a light valve, and a projection lens, wherein:

• the illumination system is adapted for providing an illumination light beam;
• the light valve is disposed on a propagation path of the illumination light beam, and is adapted for converting the illumination light beam into an image beam;
• and
• the projection lens is disposed on a propagation path of the image beam, and is adapted for projecting the image beam from the projection device, wherein the illumination system comprises a light-source module, a scattering element, and a light uniforming element, wherein:
• the light-source module is adapted for emitting the illumination light beam;
• and
• the scattering element is disposed between the light-source module and the light uniforming element, wherein the scattering element has a plurality of scattering areas with different haze values, the scattering areas comprise a first scattering area and a second scattering area, the first scattering area is close to a center of the scattering element, the second scattering area is apart from the center of the scattering element, and a haze value of the first scattering area is greater than a haze value of the second scattering area.