Projector and illumination system thereof

A projector, comprising:

• an illumination system, a light valve and a projection lens, wherein
• the illumination system comprises:
• an exciting light source, a first lens set, a first dichroic element, a wavelength-converting element and a beam splitter, wherein
• the exciting light source is configured to emit an excitation beam, wherein the excitation beam has a beam axis;
• the first lens set has a first optical axis;
• the first dichroic element is located between the first lens set and the exciting light source on a transmission path of the excitation beam, the first dichroic element is configured to reflect the excitation beam and transmit the excitation beam to the first lens set, wherein the excitation beam is incident into the first lens set in a direction parallel to the first optical axis, and the beam axis of the excitation beam incident into the first lens set is noncoaxial with the first optical axis of the first lens set;
• the wavelength-converting element is located on a transmission path of the excitation beam transmitted from the first lens set and has a reflective region and a wavelength-converting region,
• wherein when the wavelength-converting region is located on a transmission path of the excitation beam, the wavelength-converting region is configured to convert the excitation beam into a converted beam and reflect the converted beam to the first lens set, wherein the converted beam transmitted from the first lens set is used to pass through the first dichroic element;
• wherein when the reflective region is on a transmission path of the excitation beam, the reflective region is configured to reflect the excitation beam to the first lens set;
• and
• the beam splitter is located on a transmission path of the excitation beam and the converted beam transmitted from the first lens set and is configured to split the excitation beam into a first branch excitation beam and a second branch excitation beam, wherein the beam splitter allows the first branch excitation beam to pass therethrough and reflects the second branch excitation beam to the first dichroic element, the beam axis of the excitation beam incident onto the beam splitter from the first lens set is noncoaxial with the beam axis of the excitation beam incident into the first lens set from the first dichroic element, and the converted beam transmitted from the first lens set is used to pass through the beam splitter;
• the light valve is disposed on a transmission path of an illumination beam and configured to convert the illumination beam into an image beam;
• and
• the projection lens is disposed on a transmission path of the image beam.