| 摘要 |
A projection television (10) comprises a projection screen (22) formed by a three dimensional hologram (26) disposed on a film substrate (24). A projection tube and associated angled lens has an optical path (32) in a substantially orthogonal orientation with the screen (22) and two other projection tubes with associated angled mirrors have respective optical paths (34, 36) converging toward the first optical path (32) at angles of incidence alpha . The hologram (26) represents a three dimensional interference array having a configuration effective for reducing color shift in the displayed images. The screen (22) has a color shift less than or equal to approximately 5 for all angles alpha , where 0 DEG < alpha </=30 DEG , as determined by the maximum value obtained from at least one of expressions: (I) and (II) where theta is any angle within a range of horizontal viewing angles, C( theta ) is the color shift at angle theta , red ( theta ) is the red luminance level at angle theta , blue ( theta ) is the blue luminance level at angle theta and green ( theta ) is the green luminance level at angle theta . One or more lenses may be interspersed between the projection tube and the angular lens and/or between the angular lens and the screen for collecting and/or spreading the light from the projection tube. The projection is direct from the mirrors associated with the projection tubes to the screen (22), which employs the ability of the holographic screen (22) to accommodate moderately large angles of incidence while also freeing cabinet space, particularly areas in rear corners of the cabinet tapering toward the projection screen (22) at the front. |
