Optical display system including a light valve

摘要

An optical display system includes a light source, a color wheel, an optical train and a light valve. The optical train includes a diffuser element, a compound parabolic concentrator and an integrator. The diffuser element diffuses incoming light to fill in holes in cone half-angle distribution of light generated by the light source. The compound parabolic concentrator reduces the cone half-angle of the diffused light to a cone half-angle expected by the light valve. The integrator reduces hot spots in the diffused light. The color wheel may modulate optical path length of light traveling through the color wheel. Modulating the optical path length reduces coherence in the light generated by the light source. A color wheel that reduces coherence would allow the light source to be laser or LED-based. If the light valve is a ferroelectric light valve, the color wheel may include pairs of polarizers. Light is polarized in orthogonal directions by the polarizers in a pair. This allows all of the light to be used by the ferroelectric light valve during dc balancing.