Projection display apparatus

A projection display apparatus comprising:

• reflective light valves provided for R (red) light, G (green) light and B (blue) light respectively;
• polarizing beam splitters provided for the respective color lights which analyze to pick up the respective color lights that have been modulated and emitted from said reflective light valves for the respective colors;
• a cross dichroic prism on which the analyzed lights emergent from said polarizing beam splitters for the respective color lights are made incident from different surfaces respectively, said cross dichroic prism having an R light reflective dichroic film having a property of reflecting the R light and a B light reflective dichroic film having a property of reflecting the B light that are orthogonal to each other, wherein the R light is reflected by said R light reflective dichroic film, the B light is reflected by said B light reflective dichroic film, and the G light is transmitted by said R light reflective dichroic film and said B light reflective dichroic film, so that the color lights are color-composed and a composite light is emitted from the cross dichroic prism;
• a quarter wave phase plate that converts said composite light into a circularly polarized light;
• and
• a projection optical system that projects said composite light that have been converted into the circularly polarized light;
• wherein, the R light and the B light that are emergent from said polarizing beam splitters for the respective color lights and incident on said cross dichroic prism are S-polarized with respect to said R light reflective dichroic film and said B light reflective dichroic film of said cross dichroic prism, and the G light that is emergent from said polarizing beam splitter and incident on said cross dichroic prism is P-polarized with respect to said R light reflective dichroic film and said B light reflective dichroic film;
• and
• the apparatus further comprises a dichroic film disposed in at least one of optical paths of the respective color lights between polarizing splitting surfaces of said polarizing beam splitters for the respective color lights and said cross dichroic prism, which reflects such a component of the R light or the B light derived from said composite light incident on said projection optical system that has been reflected by a surface of a lens element constituting said projection optical system and incident on said cross dichroic prism after passing through said quarter wave phase plate and incident on said R light reflective dichroic film and said B light reflective dichroic film and transmitted by said R light reflective dichroic film and said B light reflective dichroic film to travel along the optical path of the G light in the reverse direction, or such a component of the G light derived from said composite light incident on said projection optical system that has been reflected by a surface of a lens element constituting said projection optical system and incident on said cross dichroic prism after passing through said quarter wave phase plate and reflected by at least one of said two dichroic films to travel along the optical path of said R light or said B light in the reverse direction, so as to deflect said R light component, said B light component or said G light component out of the optical path.

A projection display apparatus comprising:

• a reflective light valve provided for R (red) light;
• a polarizing beam splitter which analyzes to pick up the light that has been modulated and emitted from said reflective light valve for R light;
• a dichroic prism on which the analyzed light emergent from said polarizing beam splitter is made incident, said dichroic prism having an R light reflective dichroic film having a property of reflecting R light, wherein the R light is reflected by said R light reflective dichroic film and emergent from the dichroic prism;
• a quarter wave phase plate that converts the light emergent from said dichroic prism into a circularly polarized light;
• a projection optical system that projects said light that have been converted into the circularly polarized light;
• wherein, the R light emergent from said polarizing beam splitter and incident on said dichroic prism is S-polarized with respect to said R light reflective dichroic film;
• and
• said R light reflective dichroic film has a reflection/transmission boundary wavelength at the boundary of R light and G (green) light for P-polarized light that has an oscillation direction orthogonal to the oscillation direction of said S-polarized light.