Patent ID: 6698892
Filing Date: 2004-03-02
Classification: G02B,G03B,H04N

Abstract:
An image projection system comprising:a primary light source to propagate a polychromatic light along a primary light path, the polychromatic light having an emission spectrum composed of a mixture of primary colors having imbalanced emission energy contents; an auxiliary light source to propagate a compensating light to coincide with the polychromatic light at a location on the primary light path, the compensating light having a compensating emission energy content for a spectral range to offset the emission energy imbalance of the primary light source; an optical integrating device, disposed along the primary light path and optically coupled to the primary and auxiliary light sources, to receive the polychromatic and compensating lights separately prior to coincidence or combined after coincidence, to integrate the combined light and to allow the integrated combined light to exit with more balanced emission energy contents; an imaging arrangement optically coupled to the optical integrating device to project an image using the exiting light with more balanced emission energy contents; and a circuit coupled to the auxiliary light source to adjustably apply an amount of electrical energy to the auxiliary light source to adjust an intensity of the compensation emission energy of the compensating light to control a color temperature of the image projected.