Coupling prism assembly and projection system using the same

Abstract

A coupling prism assembly between a light valve and a projection lens includes a right angle prism and a wedge prism. The right angle prism has two sides of substantially the same length and a hypotenuse side. The wedge prism has a side which is adjacent the hypotenuse side of the right angle prism. The light valve is adjacent one of the two sides of the right angle prism and the projection lens is adjacent the other of the two sides of the right angle prism. Light enters the coupling prism assembly through a second side of the wedge prism, passes in substantially a straight line through the wedge prism and right angle prism to the light valve where the light is modulated. The modulated light passes back into the right angle prism and is reflected by the hypotenuse side into the projection lens. In a color projection system, the light is split into three color components. A separate light valve is provided to modulate each color component which is directed to a projection lens. A separate coupling prism assembly is adjacent each light valve to direct each color component to the light valve and direct the modulated light to the projection prism. A color combining prism assembly is provided between the coupling prism assemblies and the projection lens to combine the three modulated beams into a single beam which is directed into the projection lens.

Dependencies are inferred from the claim text.