Abstract: An illumination system for providing an illumination beam to a light valve is provided. The illumination system includes a light source, a light integration rod, a color wheel, a first focusing unit and a second focusing unit. The light source is capable of generating the illumination beam, and the light integration rod is disposed on the transmission path of the illumination beam. The first focusing unit is disposed between the integration rod and the color wheel and is capable of focusing the illumination beam onto the color wheel. The second focusing unit is disposed between the color wheel and the light valve and is capable of focusing the illumination beam onto the light valve.

Abstract: A color filtering device including a color filter, a plurality of polarization beam splitting units, a plurality of reflecting units, and a plurality of wave plates is provided. The color filter has a plurality of filtering parts and a plurality of light shielding parts alternately arranged thereon. Each of the polarization beam splitting units is disposed in front of one of the filtering parts and makes an angle with a corresponding filtering part. Each of the reflecting units is disposed in front of one of the light shielding parts and makes an angle with a corresponding light shielding part. Each of the wave plates is substantially parallel to one of the filtering parts. Each of the polarization beam splitting units is disposed between a pair of a wave plate and a filtering part. The color filtering device has both color filtering function and polarization conversion function.

Abstract: A projection apparatus including an illumination system, a reflective light valve and an imaging system is provided. The illumination system emits an illumination beam. The reflective light valve is disposed on a transmission path of the illumination beam. The imaging system includes a first lens group, a polarization beam splitter and a second lens group. The first lens group is disposed on the transmission path of the illumination beam between the illumination system and the reflective light valve. The polarization beam splitter is disposed on the transmission path of the illumination beam between the illumination system and the first lens group. The polarization beam splitter permits the illumination beam to pass through and travel to the reflective light valve. The reflective light valve modulates the illumination beam to an image beam traveling to the polarization beam splitter. The polarization beam splitter reflects the image beam to the second lens group.

Abstract: An illumination system for providing an illumination beam to a light valve is provided. The illumination system includes a light source, a light integration rod, a color wheel, a first focusing unit and a second focusing unit. The light source is capable of generating the illumination beam, and the light integration rod is disposed on the transmission path of the illumination beam. The first focusing unit is disposed between the integration rod and the color wheel and is capable of focusing the illumination beam onto the color wheel. The second focusing unit is disposed between the color wheel and the light valve and is capable of focusing the illumination beam onto the light valve.

Abstract: A color filtering device including a color filter, a plurality of polarization beam splitting units, a plurality of reflecting units, and a plurality of wave plates is provided. The color filter has a plurality of filtering parts and a plurality of light shielding parts alternately arranged thereon. Each of the polarization beam splitting units is disposed in front of one of the filtering parts and makes an angle with a corresponding filtering part. Each of the reflecting units is disposed in front of one of the light shielding parts and makes an angle with a corresponding light shielding part. Each of the wave plates is substantially parallel to one of the filtering parts. Each of the polarization beam splitting units is disposed between a pair of a wave plate and a filtering part. The color filtering device has both color filtering function and polarization conversion function.

Abstract: A lamp driving method for a projection apparatus is provided. The projection apparatus has a light valve and a lamp. The lamp driving method includes adjusting a brightness of the lamp to different values according to multiple states of the light valve. The lamp driving method improves the energy efficiency of the projection apparatus.