Illumination systems employing corrective optics for use in reduced etendue color video projection systems

A method for providing illumination, comprising:

• generating first light rays from a first arc lamp having a first arc;
• reflecting first light rays with at least a first reflecting device having a first optical axis, the first reflecting device being positioned such that the first arc is on the first optical axis, the light rays impinging on the first reflecting device at a first range of reflection angles measured between the optical axis and a point on the first reflecting device where the first light rays impinge;
• and
• positioning a first aspherical corrector plate to receive the first light rays, the first aspherical corrector plate providing a substantially constant magnification of the first arc image in at least a portion of the first range of reflection angles.

A projection system comprising:

• an illumination system comprising
• at least a first reflecting device having a first optical axis;
• a first arc lamp having an arc positioned on the first optical axis, the arc producing first light rays that impinge on the first reflecting device at a first range of reflection angles measured between the optical axis and a point on the first reflecting device where the first light rays impinge;
• and
• a first aspherical corrector plate positioned to receive the first light rays, with the first aspherical corrector plate being shaped to effectuate a substantially constant magnification of the first arc image in at least a portion of the first range of reflection angles;
• a reflective light valve optical arrangement optically coupled to illumination system;
• and
• a projection lens optically coupled to reflective light valve optical arrangement.

A system comprising:

• a video unit with an output video signal;
• and
• a projection system, coupled to video unit, to receive video signal and project video, said projection system comprising
• an illumination system comprising
• at least a first reflecting device having a first optical axis;
• a first arc lamp having an arc positioned on the first optical axis, the arc producing first light rays that impinge on the first reflecting device at a first range of reflection angles measured between the optical axis and a point on the first reflecting device where the first light rays impinge;
• and
• a first aspherical corrector plate positioned to receive the first light rays, with the first aspherical corrector plate shaped to effectuate a substantially constant magnification of the first arc image in at least a portion of the first range of reflection angles;
• a reflective light valve optical arrangement optically coupled to illumination system;
• and
• a projection lens optically coupled to reflective light valve optical arrangement.