Abstract: Apparatus and methods for mounting and aligning the optical elements of a light engine (20) for a projection image display system (21) to produce a focused, converging, high-resolution and coherent full-color image with optimized contrast and brightness. The optical elements of an illumination subsystem of the light engine are aligned to optimize the efficiency and properties of light transferred from a light source (26) to a set of three imagers (38, 40, 42). The optical elements of a projection subsystem (24) of the light engine (20) are aligned to optimize the synthesis of the three primary color components output by the imagers (38, 40, 42) to project the full-color image onto a projection screen. The alignment is achieved by apparatus and methods that accurately position the optical elements and that precisely adjust the relative positions and angular orientations of certain of the optical elements.

Abstract: An optical assembly (11) is formed by individually positioning a plurality of prisms (15) using mechanical reference surfaces (19) which are associated with the prism's diagonal (13) and are preferably formed by extensions of a first sub-prism (17A) beyond a second sub-prism (17B). The mechanical references surfaces and a first side of the prism engage fixed mechanical references (23) associated with a housing. A locking element (21) engages a second side of the prism and forces the mechanical reference surfaces and the first side of the prism against the fixed mechanical references to achieve accurate positioning of the prism's diagonal (13).

Abstract: An optical assembly (11) is formed by individually positioning a plurality of prisms (15) using mechanical reference surfaces (19) which are associated with the prism's diagonal (13) and are preferably formed by extensions of a first sub-prism (17A) beyond a second sub-prism (17B). The mechanical references surfaces and a first side of the prism engage fixed mechanical references (23) associated with a housing. A locking element (21) engages a second side of the prism and forces the mechanical reference surfaces and the first side of the prism against the fixed mechanical references to achieve accurate positioning of the prism's diagonal (13).

Abstract: Focus adjustment assemblies for projection television are provided. Locking systems are also provided which lock the barrels of the projection television in position immediately after focusing and which have a reduced risk of warping the barrels.