Abstract: A beam combining device and a projector having such a beam combining device are provided. The projector includes a first color light source, a second color light source, a third color light source, a beam combining device, a light valve and a projection unit. The first color light source, the second color light source and the third color light source respectively emit first, second and third color beams. The beam combining device includes a polarization state converting module, a color separation unit and a polarization beam splitter. The optical path lengths of the first color beam emitted from the first color light source to the polarization beam splitter, the second color beam emitted from the second color light source to the polarization beam splitter, and the third color beam emitted from the third color light source to the polarization beam splitter are equal.

Abstract: A projection apparatus includes a plurality of light sources, a dichroic prism, a plurality of integrator rods, a light-deflecting optics, a light valve and a projection lens. The dichroic prism is used for forming a combined light beam. The integrator rods are positioned between the light sources and the dichroic prism for homogenizing the light beams prior to their incidence on the dichroic prism. The light-deflecting optics is used for deflecting the combined light beam emerging from the dichroic prism, and the light valve is used for receiving and then modulating the combined light beam deflected by the light-deflecting optics to form an image beam. The projection lens is used for projecting the image beam, and its optical axis is substantially parallel to the longitudinal directions of the integrator rods.

Abstract: A projection apparatus includes a first, a second and a third light sources, a first reflective element, a first and a second dichroic mirrors, a light-homogenizing element, a light valve and a projection lens. The first reflective element is configured to reflect the first light beam, and the first dichroic mirror is configured to reflect the second light beam and to transmit the first light beam transmitted from the first reflective element. The second dichroic mirror is configured to reflect the first and the second light beams transmitted from the first dichroic mirror and to transmit the third light beam. The light-homogenizing element is used for homogenizing the combined light beam, and the light valve is used for modulating the combined light beam to form an image beam. The projection lens is used for receiving and then projecting the image beam.

Abstract: A backlight module for a display includes a light source, a lens unit, a reflective unit and a prism. The light source provides a light beam. The light beam passes through the lens unit to be expanded, then transmits to the reflective unit and reflected to the prism. The light source may be a laser source.

Abstract: An illumination system including at least one first light source, a prism and a light uniforming device is provided. The first light source is capable of providing a first beam. The prism is disposed on a transmission path of the first beam, and has four first facets. Two of the first facets are opposite to each other, and the other two first facets are opposite to each other. The first beam passes through one of the first facets and is totally internally reflected by another first facet opposite to the one of the first facets. The light uniforming device is disposed on the transmission path of the first beam from the another first facet. The cost of the illumination system is lower, and the illumination system has high flexibility of the light source design and can provide illumination with high brightness.

Abstract: An illumination system including at least one first light source, a prism and a light uniforming device is provided. The first light source is capable of providing a first beam. The prism is disposed on a transmission path of the first beam, and has four first facets. Two of the first facets are opposite to each other, and the other two first facets are opposite to each other. The first beam passes through one of the first facets and is totally internally reflected by another first facet opposite to the one of the first facets. The light uniforming device is disposed on the transmission path of the first beam from the another first facet. The cost of the illumination system is lower, and the illumination system has high flexibility of the light source design and can provide illumination with high brightness.

Abstract: An optical engine including a beam splitting and combining system, which includes a first polarizing beam splitting (PBS) unit, a dichroic unit and a second PBS unit, is provided. A first color beam is reflected by the first PBS unit, is reflected by a first light valve, and passes through the first PBS unit sequentially. A second color beam passes through the first PBS unit, is reflected by a second light valve, and is reflected by the first PBS unit sequentially. The dichroic unit is disposed on an optical path of the first and second color beams. The second PBS unit is capable of allowing a third color beam to travel to a third light valve and allowing the third color beam reflected from the third light valve to travel to the dichroic unit. The dichroic unit is capable of combining the first, second and third color beams.

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 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: 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.