| 摘要 |
A projection-type television receiver comprising right, left and center projection tubes each having a face, the images on the faces of the right and left tubes being formed in registry with the center of each corresponding face for minimizing keystone distortion and maximizing luminance in the receiver, and a transmissive screen for displaying a composite picture of images from the tubes. A lens corresponding to each tube focuses the images from the tube to form a coincident image, and mirrors reflect the coincident image onto the screen for viewing. A particular arrangement of the lenses is described for substantially uniform luminance on the screen and for a substantially symmetrical temperature distribution on the faces of the tubes. It is also preferred that each of the lenses corresponding to the left and right projection tubes have an associated center-line, and that the point of intersection of the center-line of each of the right and left lenses with the transmissive screen be offset by a fixed amount toward each lens from the point of intersection of the center line of the center lens with the transmissive screen. The angle of inclination alpha ' between each of the right and left lenses and the face of its corresponding projection tube, and the angle of inclination alpha between the center-line of each of the right and left lenses and the transmissive screen preferably satisfy the equation: 1/mxtan alpha =tan alpha ' where m is the magnification of each respective lens.
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