Illumination system and projection device

An illumination system, comprising a light source module, a light splitting and combining element, a beam expanding and collimating module, a reflecting element, and a light combining module, and the illumination system is configured to provide an illumination beam, wherein:

• the light source module is configured to emit a first color beam, a second color beam, and a third color beam;
• the light splitting element and the beam expanding and collimating module are disposed on transmission paths of the first color beam and the second color beam from the light source module and located between the light source module and the light combining module, and after the first color beam and the second color beam are transmitted to the light splitting and combining element, the first color beam and the second color beam are reflected by the light splitting and combining element, wherein the transmission paths of the first color beam and the second color beam leaving the light splitting element are coincident, and the first color beam and the second color beam from the light splitting and combining element are expanded and collimated by the beam expanding and collimating module and transmitted to the light combining module;
• the reflecting element is disposed on a transmission path of the third color beam from the light source module and located between the light source module and the light combining module, and the third color beam from the light source module is reflected by the reflecting element and transmitted to the light combining module,
• wherein the light combining module comprises a reflecting mirror and a dichroic element, the reflecting mirror is located on the transmission paths of the first color beam and the second color beam to reflect the first color beam and the second color beam from the beam expanding and collimating module to the dichroic element, the dichroic element is located on transmission paths of the third color beam, the first color beam, and the second color beam, and the dichroic element guides the first color beam and the second color beam from the reflecting mirror and the third color beam from the reflecting element to be transmitted in a same direction.

A projection device, comprising an illumination system, a light valve, and a projection lens, wherein the illumination system comprises a light source module, a light splitting and combining element, a reflecting element, a beam expanding and collimating module, and a light combining module, wherein the illumination system is configured to provide an illumination beam, the light valve is disposed on a transmission path of the illumination beam to convert the illumination beam into an image beam, and the projection lens is disposed on a transmission path of the image beam to project the image beam out of the projection device, wherein:

• the light source module is configured to generate a first color beam, a second color beam, and a third color beam;
• the light splitting element and the beam expanding and collimating module are disposed on transmission paths of the first color beam and the second color beam from the light source module and located between the light source module and the light combining module, and after the first color beam and the second color beam are transmitted to the light splitting and combining element, the first color beam and the second color beam pass through the light splitting and combining element, wherein the transmission paths of the first color beam and the second color beam leaving the light splitting element are coincident, and the first color beam and the second color beam from the light splitting and combining element are expanded and collimated by the beam expanding and collimating module and transmitted to the light combining module;
• the reflecting element is disposed on a transmission path of the third color beam from the light source module and located between the light source module and the light combining module, and the third color beam from the light source module is reflected by the reflecting element and transmitted to the light combining module;
• and
• the transmission paths of the first color beam, the second color beam, and the third color beam after leaving the light combining module are coincident, and the illumination beam comprises at least one of the first color beam, the second color beam, and the third color beam.