Illumination system, control unit thereof and projection apparatus using the same

A projection apparatus, comprising:

• an illumination system adapted to provide an illumination beam, the illumination system comprising:
• a first exciting light source adapted to provide a first exciting beam;
• a second exciting light source adapted to provide a second exciting beam;
• and
• a wavelength-converting wheel disposed on a transmission path of the first exciting beam and the second exciting beam, wherein the wavelength-converting wheel has a first annular irradiation portion and a second annular irradiation portion, the first annular irradiation portion has a first light reflecting region and a first light converting region, the first light reflecting region is adapted to reflect the first exciting beam, the first light converting region is adapted to convert the first exciting beam into a first converted beam and reflect the first converted beam, the second annular irradiation portion has a second light reflecting region and a second light converting region, the second light reflecting region is adapted to reflect the second exciting beam, the second light converting region is adapted to convert the second exciting beam into a second converted beam and reflect the second converted beam, wherein the illumination beam comprises the first exciting beam, the first converted beam, the second exciting beam, and the second converted beam;
• a light valve, disposed on a transmission path of the illumination beam and adapted to convert the illumination beam into an image beam;
• and
• a projection lens, disposed on a transmission path of the image beam and adapted to allow the image beam to pass therethrough.